fiberglass layup [Archive] - Scream And Fly Powerboat and High Performance Powerboating Discussion Forums

Techno

10-27-2002, 09:42 PM

Someone is going to say I'm wrong but I don't use mat unless there is a reason to. It's weaker than cloth/holds more resin.
Some say that the mat is needed for a pre-bond to the wood then cloth can be used. I don't understand it and haven't had a problem yet. But then again whenever I bond to wood I always use epoxy so that might be why.
The mat is used as a surfacer so the cloth doesn't print through.
Mat also forms easier than cloth, like on the stringer edges.

I would go with 2-3 layers of 6 oz. cloth using epoxy. Slop the wood up good first so it is sealed, then go with the glass.
Plastic sheet can be used on the edges if they won't stay stuck down.

This is just an opinion and I don't do this everyday like some of the other glassers.

175checkmate

10-27-2002, 10:08 PM

I'll have to keep a close eye on this thread.

BenKeith

10-27-2002, 10:13 PM

I'm with Techno if you want a light layup. Several layers of cloth will be stronger than the same thickness of mat. Mat is great and very strong if you sandwich it in between two cloths or woven roven, but it's also very heavy unless you really work it down to get all the excess resin out. Like Techo says, it holds a lot of resin. You can lay a layer of cloth over it and using a roller, keep working the cloth down and pushing the resin out but usually doing a large area you don't have the time before it cures. Then you start getting high a low spots trying to work another section next to the one that has cured.

patchesII

10-28-2002, 07:41 AM

keep them coming. thanks, erik kiser

vector mike

10-28-2002, 12:16 PM

I use cloth or woven roven for all my high stress areas and matting for filling in or low stress areas. Woven roven is the strongest but also the heavyist. The only problem I have with cloth is that it doesn't like to form sharp edges. Depending on where the glass is being applied is how I determine which type I use. :)

sho305

10-28-2002, 01:14 PM

I used a paint brush on my cheezy transom, but yes the cloth lays out nice and the mat just sucks up resin like a sponge. You guys need to tell us idoits how to use the plastic wrap to do corners, and the roller thing. I wish I had one when I did it. I had the thin cloth you get anywhere and put about 4 layers on inside of transom, originaly there was 1 or 2. It is only 90hp anyway, but I wonder if I woulda beefed it up for my 150? Naw, its a Bayliner!!!:cool:

Techno

10-28-2002, 07:21 PM

Don't go crazy and use this the wrong way
The absolute strongest is unidirectional. Next is the skip weave( binding weave whatever it's called), next is biaxial and then cloth. Roven roving actually isn't as strong as you think, it's a loose cloth made with larger yarns. It stronger because it's heavier, 28 oz per yard instead of 6. So one layer of roving and it's pretty much done.
The weakness comes from the stress of the fibers passing under over each other. When this is reduced or eliminated the weight is stronger.
Mat is supposed to be wetter I think ~65% resin content. It's supposed to hold more, don't try reducing it. That percentage is also a weight thing. 8 oz. of mat should be 35% of the total wieght, I'm not sure it's 65% though. might be lower.

The plastic trick is after wetting out the- whatever- you cover it with a sheet of plastic and smooth it out. This isn't the best method but only a technique. It doesn't remove excess resin but helps plaster the material down, if it still don't stay you can weight it or hold it by hand. maybe staple it.

On the topic of excess resin. The mat, cloth or roving is supposed to hold a percentage of resin, any more and its a waste and heavier, possibly weaker (more resin between layers) If I can pour the resin on and use a squeegee I will. a laminate roller is just used to get the bubbles out and squeeze everything down. a regular roller sucks up too much resin in my opinion so I don't use them anymore.
The best method hands down for laminating is doing it horzontal. Pour the resin on spread it out with a squeegee, place the glass, pour squeeg, repeat until done. On the last layer squeegee the excess right off the side. Light strokes with a bondo squeege.

Heres a top hat stiffener I made from a whole bunch of stuff. If I remember right bottom up. 6oz. cloth, roving,cloth unidirection graphite, cloth. The wooden mold made it easy. You can see the result of covering it with plastic, the surface is resin rich. Used epoxy. Marked a sheet of plastic on the back for the edges. laminated flat. flipped onto the wood mold and clamped it up.

Think out what your going to do and see if there is an easier way. One method is to wet out cloth on plastic and flip it in place. Remove the plastic and repeat. This should be tried first if you've never done it.

Jacob

10-28-2002, 10:30 PM

What about knitex techno? It's what we use to build our boats.I belive it's a 45 degree weave(it may be 60 I'm not positive). What's your opinion on it.

sho305

10-28-2002, 11:50 PM

Woah, I'm palying catch-up here! I think I had one chunk of thicker mat, the stuff going everywhere and loose. I had painted the board good before install w/epoxy, and put this on there over the new and about 6" into the old at the kinda knees they have there. Just enough to wet it good, had to cut holes and pour in seams to get bubbles at edge of board. Then ground it lightly to get smooth and put a layer of cloth, (thin burlap looking stuff from US Boats?) over it all and then another over the area of the bolts, maybe 6"x12". The Epoxy dried fast, 5-10min working time. Board was only maybe 18" wide in Bayliner. Did some other areas in there for strength.

Outside: I ground old shell and replaced bad areas where motor had busted through(I had cut outside away with grinder & 1/8 cutoff wheel to access rotten wood, would remove well next time). Slopped it up and screwed it good w/SS screws. Then ground it tapered and laid 2-3 layers cloth maybe 2" wide deep in seams. Had one layer on new board too. Glassed an edge across top so I could fill transom with resin, last 1/8" of so inside there. Filled seams mostly with epoxy and filler mixture, then got mad at end and used duroglass. Painted it good with epoxy to seal duroglass(?), sanded, and Painted with VC Performance Epoxy.

Did lots of cavitating holeshots and stuff trying to put force on the transom for 24 gallons of fuel. Been 3 months and it looks flawless yet. Painted motor bolt holes & drains with epoxy, then glued the whole motor and transom cover on with-I think it is 3M 5200. Wicked stuff.

This seems to be great for this boat, but I obviously need to improve my technique for more important projects. :) Thanks for the info! This started for fun, but then I figured I had better do it close to good or I would not learn anything:D

Alan Power

10-29-2002, 01:52 PM

If you can describe what you are trying to do exactly, I can point you in the right direction, yes unidirectional is a very strong cloth but with its fibre orientation mainly in one direction mainly all its strenght lies in that direction.
Then there are the woven rovings a loose cloth and is the most common reinforcemen- plain weave over/under, satin weave over2/under2 and knitted fabric with its strands superimposed, (not woven), and stitched together.
Glass mat has equal strenght and modulus in all directions, woven materials and knitted fabrics are stronger in the direction of their strands, (warp and weft, 0 and 90 degrees), but have much less strenght in the 45 degree at this angle mat is much stronger. This is the main reason for using alternate layers of mat and cloth.
Glass content in a laminate for mat ranges from 22%-33% and rovings 33% - 50%.

If you need any other information you can email me or I'll check back here later.

Alan...

175checkmate

10-29-2002, 04:45 PM

Going to be adding stringers and knees to the checkmate. Weight is not a problem, will also have to redo the floor. Looking to make it stronger and reduce flex. Will also be adding a pad. I have an idea how to make the form for the pad but not sure of witch glass to use.
Thanks for the help

Alan Power

10-29-2002, 05:32 PM

First of all give me an idea of what is already in the boat, stringers, knees etc. What is being replaced, what is being left and what is aditional. The knee's I presume are your transom knees which join your transom to stringers, how many and how big, any pics would be great.
What flex do you wish to reduce? Is this mainly a transom stiffening job?
As for the pad this is an external job, what material are you using for the form and have you had much experiance with laminating glass?

Alan..

sho305

10-29-2002, 06:08 PM

Wanted to toss in one detail: If you get it done, and then figure you can put a jack or setback on there so you can change motors without disturbing the transom again...is there anything you can do differently with the transom for better mounting/longevity? Or just bolt it on there and seal it good like a motor. I mean like glass the bolts in or something while you are glassing the transom for example, but I know glass will not seal bolts of course.

I painted in the holes with epoxy, then used 3M 5200--is that good?

My Checkmate has this metal guard over the transom and is raised 2". I would raise it to 22-23" what ever it should be now, but should I get another guard? Make the transom better (knees that I would use anyway)and forget the guard? I think it is 19", maybe forget changing it and put the jack on?

175checkmate

10-29-2002, 08:46 PM

I will be tearing everything out this weekend. I will take lots of pictures and we will go from there. PM me you e-mail address and I'll send them to ya.
Thanks for the help.

Techno

10-29-2002, 09:34 PM

What I do is redrill the holes large enough for pipe nipples. Brass or SS. The hole should be bigger than the nipple, not a tight fit. Epoxy the wood and let it set. Then bond in the pipe nipple with thickened epoxy. The nipple can be drilled to the right bolt size if too small. The worse the outside of the nipple the better, the grooves or scratches give it tooth. This is a method from gougans broth. book for holding on multi ton keels, and being removable.
This means you need about a 3/4" cut down shank drill, or equivalant.

The final result is the wooden transom is sealed so can't rot ever again. At least from the fasteners.
The nipple is gripping the circumference of the hole so adds surface area internally, which a regular bolt doesn't do. This comes out to about 5 sq. in. for a 2" thick transom. 4 bolts is almost 20 square inchs of free support.
The bolt is clamping onto the nipple and can't crush so the torque value remains consistant. The nipples should be flush with the surfaces.
Any leaks are internal to the nipple so don't affect the wood.
The bolt can't rasp the wood hole if it gets shaken.

I did this for the engine mounts and the tie down brackets. Any through bolts on the knees.

For non through fasteners. Drill a much larger hole and leave a tiny pilot hole in the center, bottom. Set the screw in the pilot hole and fill with filled epoxy. OR
Fill the over sized hole with filled epoxy, drill and tap for a machine screw.

If you don't do the pipe nipple method- when you seal the bolts dont' seal the inside side. This way if the bolt is leaking you know it and can fix it before it rots the transom. Try slathering a bolt up with sealant, sticking it in a hole, remove the next day. Very little sealant is there. Most gets pushed off when you slide it in. If the bolt leaks but is sealed on the inside side then the water has access to the wood. But since it doesn't leak into the boat it seems OK.

Treat the wood like it should never be violated and it shouldn't rot again. Screws driven into it to hold the rub rail are like a nail in the coffin.

175checkmate

10-29-2002, 10:05 PM

Do you have a picture of the fitting you used in the transom.
Sounds like a great idea.

sho305

10-30-2002, 09:22 AM

Why didn't I think of that?? Great tip, I will be on that. I would like to put metal in there too, but that would be difficult, and likely don't need it if knees are used anyway.

Techno

10-30-2002, 05:29 PM

The fitting is just a pipe nipple. I think the engine bolts are 1/2" so the pipe nipple is 1/2" Keep the threads on and scuff up the area between them. Get it the length of the transom thickness and set it flush, then file or whatever to the surface inside or outside, whichever you prefer.

The tie down rings were something like 5/16" and the pipe nipple was too small. I drilled it out so it fit.

In a picture nothing really shows and now that it's painted doesn't show at all.

This drawing is close to scale. but the wall thickness is made up. The red is the transom.
Purple would be the epoxy filler but doesn't have to be thick.
Orange is the nipple.

Butter the nipple up with filler and insert. Then take a popsicle stick or putty knife and keep pressing more in the gap until it's filled. It can only squeeze in the gap or around the knife so it takes a little patience.

Alan Power

10-30-2002, 08:15 PM

Hey techno Nice work, I've just replaced a rotten transom in my boat, dont want to be doing that again. The previous owner cut the transom height down for a shorter O/B and didnt seal it again.
But gave me a good opertunity to strenghten up!

What did you do to the inside of your transom to spread bolt load?

sho305

10-30-2002, 10:16 PM

Mine was only a 85hp, so I figured the washers were ok with some extra mat in that spot. But if I do my Checkmate up for 200hp(I was recommended 20" of setback for this hull!!!) I am wondering about further measures for strength. Like maybe some aluminum?

Great illustration there!

Got me a scanner today for $20 at OfficeMax! Hope to get it going in a day or two, have pics of Bayliner and others to scan in.:D

Techno

10-30-2002, 11:08 PM

I might put some aluminum plate or just make some aluminum washers with a hole saw.
The nipple is gripping the inside of the transom now so there isn't a great need to spread the bolts clamping force. It's already being done with the nipple internally.
This may not seem strong but they did tests with bolts and stuff. If you want you can always test this in a peice of scrap to find out what the pull out strength is.

AlaskaStreamin

10-31-2002, 02:18 AM

Hi guys,
Just to clear up the Mat issue,...here we go; Mat should be used between woven roving and cloth to fill in the voids left by the weave. Without it you get resin pockets and as we all know, resin by its self is very brittle. They make a 3/4 oz mat which is 1/2 the thickness of regular mat. It wets out much nicer and doesn't swell up like the 1 1/2 oz stuff. On wood I thin out the resin 10% with styrene and roll a coat on and let dry. This penetrates the wood fibers and seals them. Next I put on a layer of 3/4 oz mat, a light woven roving (24 oz I think), another mat , and a final woven roving or a cloth. The key is to work all the layers without letting it set up. Use a ribbed roller to work out any air bubbles and excess resin between layers. A 4" paint roller works really well at getting the resin on fast. If you are adding knee braces, etc., run a 3/4" radius router bit along the outside edges. The fiberglass will make these corners without puckering. Hope this helps. Also you can go to this link from the IHR and see how I layed up my kids 9' Virages. Good luck and have fun!!!;) http://www.hydrostream.org/ArticleArchives/BabyVirage/BabyVirPartII.htm

sho305

10-31-2002, 08:40 AM

I'd guess the lower bolts only get pull reversing or if you hit something. I am thinking mostly about having this close to 20" setback I was recommended, as the Checkmate is bow-heavy. Then with 300+lbs motor out there, the static weight over time has to be a lot, say when on the trailer(most of the time). The knees do the bottom nice, but the top is free. Would be nice to run an anluminum bar on the top and into the sides of the well to spread the weight out to the sides. That would be a pain as well as you have to offset inwards to be inside the transom when going through the well. Maybe that 4-5" above the well will not flex/warp anyway? I guess 1.5" of good plywood will hold alot at 6". As mine is weak now, and being raised 2", that is where it moves when I jump on the motor.
Can you believe those big ugly bolts used to mount the trim pump on the right side there??? Duh.
I know it is leaking now; if you look hard you can see bolt holes below the motor I tried to goop up. This is where they mounted a 200hp on there. He said they did not like it, and I bet it handled bad and chinewalked, etc. I would hope a setback would change that...or a pad if I have to.

175checkmate

10-31-2002, 09:08 AM

Do you have any other pictures of the c-mate. Like how the interior is set up? I would like to compare it to mine.

sho305

10-31-2002, 09:16 AM

You gonna make me put pics of my ugly faded out boat on here?? You are heartless!!! Inside looks the worst, I'll see what I got here...

sho305

10-31-2002, 09:18 AM

BR area

sho305

10-31-2002, 09:24 AM

Supposed tri-hull, if you want to call it that. I say vee with splash control. Does corner great at speed though.

sho305

10-31-2002, 09:41 AM

Not having one of the floor in there, likely as it is ugly. Carpet shot and back seat redone very poorly. The floor is only about 2-2.5' between the front seat pedestals(they are about foot square) and is the bottom from there up to side. Inverted 'trihull' makes a nice cubby down each side with a little trim panel about 4" high to hold stuff. Floor steps up maybe 4-6" at windshield to little BR area. Seats are on floor in BR area and bottom seat goes all the way across. Larger cubby door in bow/nose. No floatation. Used to be upholstered panels on sides of cockpit, like behind throttle control all the way down sides and is gone You can see them still there in the BR area, maybe 6" high on the sides.

Now this is the way you pull your boat around if you are THE MAN:D :p :cool: If I could only figure out how to get it to pull the trailer up the ramp when the boat was on it now...

Techno

10-31-2002, 05:07 PM

I used to think the bottom bolts didn't do a whole lot, then I thought of TURNING! They go in stress side to side too.

If your looking for a method of splashing the boat a guy on a channel near here uses a winter beater as a trailer machine. The dudes got a ramp and just pulls it out or backs it in. Easier than a boat lift and quicker. Hooked up all the time just outside his door. I guess he uses the car during the winter.

Reese

10-31-2002, 05:43 PM

The only comment I would add to this thread is…to be careful when using fiberglass as a structural material over wood. By structural I mean as a primary material that is used to support the load.

I’ve seen quite a few designs that simply butt up the plywood knee brace to transom with several layer of laminated fiberglass (cloth, mat, roving) for support. The only thing that is supporting the knee brace is a thin (first layer) of resin and fiberglass.

Over time this bond can be weakened by moisture resulting in delaminating from the wood structure. I only use fiberglass to seal the wood and quite frankly it’s barely adequate at that task…fiberglass/resin bonds fairly well to itself but not much else.

Here is a picture of the back end of my boat…it used to have an open splashwell that I closed off. The substructure is made of wood that is bonded (polyurethane glue) to the fiberglass. All of the wood is then sealed inside and out with laminating resin and finished with Kitty hair fiberglass Bondo.

Reese

10-31-2002, 05:54 PM

BTW...

I know there are a lot of people who are; planning projects, starting projects and finishing up projects.

What do you think about a "Projects" section...I know we have a ton of links to manage but speaking for myself it would be very motivational and helpful to see others sweating and itching along with the rest of us.

It would also be nice to see the final results...especially if the bottoms have been modified along the way.

sho305

10-31-2002, 07:47 PM

You know Reese, thats a damn good idea! You want to post it to 'ideas'? Or do you have a better connection here? I just got a scanner, have to hook it up, and I have some snapshots of my Bayliner's simple transom repair I can post and what I was doing. It was work, but was only about 18" wide, not the whole stern. there are some good threads on exhaust mods and such that could be put there "how to's" or "I did's". That would be great.

Boy, that looks just like duroglass on the back of that boat, all the green stuff. It is hard as a rock! You are deep into that one, and looks like it will be nice when done.

Techno- Though of that, then sold my beater ranger 4x4 for $800 a couple of years ago. Got to have a 4x4 at our crappy ramp. Just did not want it sitting around there, and then it would break or something...Would like to have something like that or a lift. It is muddy where I am though. Thought about putting some tracks in with a trailer on them, and using a winch or something. If my truck is not there somebody will pull it for me, but every weekend is getting old.

Reese

10-31-2002, 08:05 PM

To be honest I don't know anyone on this site...just been following a few projects like scott's and techno's.

I think it would be interesting to see what everyone is working on...especially during the winter!!!

I may just post to either the general or technical discussion and title it "Scream and Fly- Member Projects".

BajaSS235

10-31-2002, 11:59 PM

Post the Idea , Title it somthing like (hey Greg how about )
He (Greg) is very responsive to the requests of the members here.
I'm sure if we show enough interest he'll set up a section for it

Baja

sho305

11-01-2002, 08:57 AM

I posted in Ideas, toss in your .02 there about a projects and/or howto's section and what needs to be there. Got into the 20s here last night...not wanting to go outside...:eek: Have to get that furnace working in the barn:)

http://forums.screamandfly.com/forums/showthread.php?s=&postid=151269#post151269

Alan Power

11-01-2002, 10:21 AM

Thats such a good idea, I'm new here too and am still only finding my way around, mainly looking for people with projects on the go like myself.

I have completely stripped all the wood from my boat and replaced everything, I am now at the fun part of putting the boat back together. I would reay like to see other peoples work to see what they have done.

And a 'how-to' section would be great, theres plenty I want to know how to do!!!:confused:

An engine mod section maybe?

Reese

11-01-2002, 03:23 PM

I posted a new thread on the Technical forum titled "Scream Team Projects".

Anyone who would like to see a new forum that is specifically geared twards members projects please make your opinion known.

blyguy

11-16-2002, 11:36 AM

Do you have any more pictures of your project. I have a Checkmate Enchanter I would like to add a setback to and also remove the splashwell to replace with a sun deck. I thought about purchasing a setback. Stainless marine and a few other vendors carry them. They are not cheap. I like your idea of building you own.

My brother and I have done some glass work. More so him than I. He had a 70's Vampire he cut in half and removed 2 1/2 feet and put it back together. I still wonder why he did it, but that's besides the point. I bought the boat from him for near nothing and kept the motor. I did run it a few years until I bought the Checkmate.

Some day I would like an open bow, but I am not ready to cut a hole in the cap yet. Plan to do the sun deck over the winter.

Reese

11-18-2002, 01:51 PM

I have lots of pictures but not converted to digital… I’m not sure if it they will be of much help but I’ll try and get some up this week.

In the mean time why don’t you start a new thread and post some pictures of you checkmate along with what you plan to do, that way we can all follow along and throw in some design ideas.

Closing off the splashwell seems pretty straight forward until you get into it…then you realize that there are many things to consider including the relationship between the engine and the new closed deck.

You are correct that you’ll probably need some amount of backset to clear the deck (if you want to tilt the engine). I strongly suggest you use at least a manual jackplate (I use a 5 ½" CMC) along with what every stationary backset you fabricate…you will also need some sort of knee brace to support to support the hole thing.

The best thing I did before I ever started was to carefully draw everything to scale and plan accordingly…It saved my ass more than once. Here is the picture of the knee brace/backset which supports 100% of the engine weight, the rest of the transom is only ¾” thick called a false transom.

blyguy

11-18-2002, 02:54 PM

Was this false transom the original transom? Or was this an I/O looks like it could have been. When I start I will start a new tread with pictures. I do not really want to cut through my original transom, which may be all the more reason to just support current transom add setback and cap the splashwell.

Reese

11-18-2002, 03:23 PM

I agree with you...don't cut your original transom!!!

My transom was shot and I decided to do something a little different...the transom you see is a complete redesign, nothing in the picture came with the orginal boat.

The boat had an open splashwell with the engine directly mounted on a 2" thick transom. I closed that off and added the backset and swim steps.

Adding knee braces to your original transom is perfectly adequate. By all means use as much of the original deck, transom, etc. as you can, it will make life a lot easier.

AlaskaStreamin

11-18-2002, 06:51 PM

Here's a Glasply I did a few years ago. I had to replace the transom due to rot. I built a swimstep / pod and added it on the back. I made a mold and made the rear gunnel from the rubrail up across the transom. This boat was origionally an outboard version with a well. I gained a ton of room w/o the splash well and getting the motor back balanced the boat great. If you're dealing with a high transom, I believe 32" is the minimum setback to clear the cowl.

p.s. I agree, we need a projects forum.