Mat, woven, or cloth?

[reelfishin]

I am about to start redoing a transom on a boat in which the inner skin of fiberglass will not survive. On all others I've done so far I've been able to reuse the original inner skin by just re-laminating it back on and fairing it in on the sides, the result has always been a very original look.
On this boat the inner skin is too batterer up to reuse, I will have to replace it. The original skin looks to be just a very thin layer of random direction glass fibers on the wood transom.
I will be using epoxy for the repairs.
My question is, what is the best material to put back? I was thinking just several layers of fiberglass cloth?
I have been getting my fiberglass from a local shop here, mostly I get cut offs of scraps from their manufacturing process. The weight and type of glass varies and there's usually a pretty big assortment. They sell it to me in cardboard barrels, most pieces are far larger than I need for any transom job.
The thickness varies as does the type of fiberglass mat or cloth.
The most common is a fairly heavy woven cloth which most resembles a basket weave or burlap type weave, then the next most common is a straight very thin crisscross lightly woven cloth, much like you get at Walmart in the auto section in those small bags, and then a lot of fairly thick random direction glass 'mat' which has no woven in it at all, its just pressed fibers. I've not used the random direction mat since it don't soak up epoxy well without a lot of thinning, I've been using the woven cloth in between all layers in the transom, and using the thinner cloth and some thinner mat for fairing the edges.

On this boat, the transom inner skin is so thin it all but fell apart when the wood rotted, it broke up like dry paper.
If I want it to match the rest of the boat, I'd have to use the random mat and do some additional glassing around the edges. The original transom's inner skin isn't very well attached to the boats sides, the layer of glass isn't much thicker than a good coat of paint. The motor on this boat will be an older clamp on Mercury with only two lower bolts, so I will also be adding an aluminum clamping plate to protect the fiberglass up top.

Which type of glass should I use for the inner skin?

 

[oops!]

Re: Mat, woven, or cloth?

reel use what ever you want...!!

your using epoxy....so you dont need the csm to be between the substraight and the laminate material......

all you are trying to do is water proof the transom.....you dont add much stregnth by glassing the main area of the transom....the tabbing is where all the stregnth comes from. so you can use the big roving......or the finishing layer of veil....(however i dont use epoxy....so a finishing veil raw on a transom....to me.....well thats just wrong.......but the epoxy is strong enough to do it)

the charts and graphs on epoxy coating....say there is a huge difference between the waterproofing capabilities of epoxy between the third coating and the fourth coating.......

just make sure that the hull and transom joints are well tabbed.

cheers
oops

 

[reelfishin]

Re: Mat, woven, or cloth?

What I've been doing is dry fitting each panel of the transom to a near zero tolerance fit, then a coating of epoxy, a layer of fiberglass cloth just saturated with epoxy, then a well coated second panel. I usually fill the edges well with thickened resin. I 'wrap' the last layer of glass around the corner onto the sides and deck about 12" after a grinding it with a course sanding disc. So far the results have all been great. This is actually only the second straight transom I've had to do, all but one so far have been curved. I have three more here I plan to do over the winter too, this one now is the easiest though.

I had considered Seacast but I just can't justify the cost and sealing the lower edges of the transom cavity, building a suitable inner and outer frame or support would be as much work or more than just doing it in wood in the first place.

I'm not sure I am really clear on what the right terminology is for the various types of fiberglass, so far I've pretty much avoided the random fiber type mat just since it soaks up so much resin, and I really didn't feel like it was getting fully saturated. It's pressed pretty tight, I think I may have to thin the epoxy to use that for the final layer. It also may be too thick when all done. I don't want to add too much width, simply adding the individual layers of resin and glass in between each layer of transom wood adds enough. It's not too bad when I can use two 3/4" layers but when I have to make a curved transom and it ends up being either four 3/8" or 6 1/4" layers of ply it can come close to being too thick. On models where the splash well bolts in place, I've had to refit the splashwell on a few to make it all work. On the ones with 6 layers of 1/4", it adds about 3/16' or so which is no problem so long as I don't over do the inner skin.

Any ideas on adding a permanent clamp guard to a transom? Glassed in place strip of stainless or aluminum, rather than screwing it into the fresh transom when all is done and having to worry about sealing the holes?

I have done a couple by making a new top cap out of aluminum U channel bent up from 1/8" aluminum sheet.

I did one using 2x3" ID extruded aluminum tubing and cutting off one short side making a finished looking transom cap to protect the new glass work. The added depth forms a clamp guard on the inside and I use an aluminum motor plate on the outside to level the outer transom and to meet up to the same level as the transom cap. This protects the glass and more evenly distributes the bolt load on the surface glass.

Not many boats with aluminum caps which are in need of a transom job usually have reusable aluminum caps, most are well worn, corroded, cracked or just plain missing.

 

[oops!]

Re: Mat, woven, or cloth?

as far as the termi9noligy on the matt, cloths,,, ect......the whole reason for the chopped strand matt....is to thicken and bond....so it will drink resin....

here is a link that might help....

http://forums.iboats.com/showthread.php?t=272983&highlight=confused+on+matt+cloth

i have seen lots of boats that have chunk of alum to bolt to......that way the motor clamps wont go thru the new wood.....


hope that helps ya
cheers bud
oops

 

[reelfishin]

Re: Mat, woven, or cloth?

The thicker matt I have is what they describe as CSM, it's really thick, one layer is as thick as the hull itself is.
The thinner cloth is indeed like the stuff from Walmart, or veil, and the most common cloth I have is a fairly thick woven type which is about as thick as a burlap sack, about 4 times heavier than the thinner cloth.
I have some thinner matt but it's not as common to find.

I buy it from a local shop which uses it in bulk, not for boating purposes. I buy it in bulk barrels of random pieces, its far cheaper than to buy just what I need for each job, pennies actually. I buy my epoxy from one of several industrial suppliers, I use epoxy for three reasons, first off it bonds much better and is obviously stronger, I've been using epoxy for years on other various projects, and above all, I get it nearly for the same price I can buy poly resin for. Mainly the latter is since I have a wholesale source for epoxy, but not poly resin.
I also like the extended work time of epoxy, which amounts to much less waste.

The boat I am doing now will be a simple, flat two layer of 3/4" ply transom panel with a new inner glass layer. I will grind the inside of the outer skin clean, apply a fairly heavy coat of epoxy, then a layer of thin cloth between the first plywood panel and the outer skin, then a layer of heavier cloth, well soaked with epoxy and then the final plywood panel. (Both plywood panels are first cut and well coated individually with epoxy). When that sets up, I'll make certain to fill any voids with a mix of epoxy resin and chopped glass,, then I'll begin tabbing the sides to the main hull and ad the final inside layer of glass. It will end up slightly thicker than the original transom but be much stronger and hopefully out last me. The last step is to drill and install all the drain tubes and drilled holes, filling each hole with resin to seal any exposed wood.

The only set back I'll have to deal with is lack of space, I can only get two boats inside at a time. I'm working on getting three inside but it will mean some major rearranging and some talented packing and shelf building to make the most of the space I have.

 

[oops!]

Re: Mat, woven, or cloth?

im not sure what the csm is that you have is......as the thickest ive seen is a 2 oz....(its really thick).

your process that you described is sound.....just make sure that the transom hull tabbing is done in a woven type of a product......

with epoxy.....man ittl be crazy strong !

as far as the shop arranging......do you have a floor jack?......we regularly take boats......stuff them in with a fork lift......then manipulste (or show horn) them into a really tight area with a floor jack......we can make it so tight in some of the shops, that the only way to get from back to front is thru the boats !

 

[reelfishin]

Re: Mat, woven, or cloth?

I built a half dozen steel dollies with wood bunks on them, I can lift the boat with a gantry crane onto the dolly. I used casters with 8" wheels from some egg shipping carts. Being on two long bunks seems more stable than trying to do any major glass work on a roller trailer.

The gantry crane I have was built originally for lifting horses, not sure how or why, but it came from a stable with a huge sling. I have several 6" wide straps and two overhead hoists, all of which is serious overkill for what I am doing but I had acquired it in a buyout a few years ago. The biggest problem I have is that the shop is basically set up as a light fabrication and machine shop, all of which must stay functional. I'm working on rearranging some of the larger equipment and welding tables to better allow these kinds of projects.
I no longer run a business out of the shop, so it's all pretty much just for my own personal use now. There's not much I can't handle when it comes to repairs.

The shop is about 25' x 50' with about 1/3 being dedicated to machine shop and welding, and the rest is random equipment and tools. I am working on moving a 4x10' welding table, if I can relocate that, I'm home free. It pretty much divides the shop in half right now, blocking lots of open floor space.

 

[oops!]

Re: Mat, woven, or cloth?

20 x 50 fully equipped shop with a gantry crane?

drool drool

ahhhhhhhh i can dream

 

[reelfishin]

Re: Mat, woven, or cloth?

My two biggest problems are lack of ceiling height, (only about 11'), and poor heating. The heating system is just an old oil furnace and some crude duct work, it just barely gets the job done. It was fine for when the main job at hand was mostly welding, but it don't cut it for glass work or painting. With the latest prices for heating oil, I won't be running the heat any more than I need to either. I still have some warm weather to work in and the building for some reason holds heat well, the roof is black coated steel and it heats up well in the daytime, if I keep the doors closed at night, it will stay warm all night on all but the coldest days. It stays comfortable enough to work without an jacket inside but not always warm enough to lay up any glass if it's really cold out. If I do any glass work and need it to stay really warm overnight, I'll turn on a couple of heat lamps on the work at hand. I've had no problems so far.

I am not only going to have to find room to fit one more boat inside, I just bought two large glass bead cabinets which will need to be set up too. (I want to have two different types of media ready to use, most likely one with plain sand or aluminum oxide, and one with either glass bead or even walnut shells.

I also need to find a way to store outboards, I have about 50 or so on various types of stands, and only one big run stand and tank. I passed up an OEM BRP/Evinrude test tank last week due to lack of space. It would have been great to have but I can't spare the space for something that wouldn't get used all that often. (A steel test stand and cut off barrel will have to do for now). I've been selling off all of the V6 motors since I really didn't plan to use them with the price of gas lately, which bought me some space. All of them are on wheels but some stands with motors store better than others.

I've been working on putting up a new garage at home but it's not likely I'd be able to get even close to what I have in size and my house taxes would increase far more than what it cost me in rent now. The only advantage would be that it was new with good heat, and of course, right in my back yard. I'd lose lots of space though.