Canadian Canoe Routes

How many layers of glass?
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Author:  GQGeek81 [ June 26th, 2005, 10:37 pm ]
Post subject:  How many layers of glass?

Need a third seat for the middle. I've got a stadium seat style canoe seat that I can put on top so the shape doesn't nead to be ergonmic really. I was thinking I'd just make a wanigan sized to work as the seat. I have plenty of glass laying around and the resin but I haven't got a clue how I figure out how thick to make the walls and lid to support the weight.

Any ideas?

Author:  Komatiq [ June 26th, 2005, 11:06 pm ]
Post subject:  Glassing..............

Hi GQ,
on your glass question are you building a box that you can put a seat on?

What type of glass on hand (woven ot mat) and what type of resin (poly, vinyl or epoxy?)

Author:  GQGeek81 [ June 27th, 2005, 7:55 am ]
Post subject:  re

I may still have some S-Glass but I think I'm just going to use some cheap E-glass and matt I have left over. This is the stuff you get an automotive stores. I'll have to dig it out to figure out the weight.

I have some silver tip resin and then I still have a bunch of cheap bondo stuff as well I need to get rid of.

I'm thinking about taking some cardboard and duct taping it inside the canoe hull to make a form for the four sides. Then cover the inside with plastic and maybe put some wax in the corners. Lay up a layer or two of glass to start with and once its set up pull that out and continue to add layers to it as needed.

This will give me a form that will match the inside perfectly and should mate with the keel line on the inside which will keep the box from being able to slide side to side.

Author:  Jwinters [ June 27th, 2005, 9:23 am ]
Post subject: 

Assuming you want to keep the wanigan as light as possible I would try making it with no more than three layers of 6 oz cloth (or one layer of 1.5 oz mat. After you have it made you can carefully sit on it and then add some wood stiffeners if you need them. I am guessing you don't want to fool with a cored laminate but if you do 1/4" of foam (like Klegecel or similar) with 6 oz glass on each side should do the job.

Author:  Komatiq [ June 27th, 2005, 11:47 am ]
Post subject:  Start light.............

The cardboard works great for a quick mold and it's fairly simple to fit as you said.

Might want to use wax paper instead of plastic, less problems with gas bubbles forming. Tape the seams and you're ready to go.

Bondo works great for the doing the corner radius. Tucking glass into a 90 deg corner is just no fun.

John was bang on with the "light" laminate approach, easy to add more for corner stiffeners and bracing........ grinding away excess is my least favorite part glass work.

Putting mat on each side of woven material usually allows for a cleaner look to the finish product and there is less tendency for the resin to drain away on the sides.

Hope there is something in there you can use.


Author:  GQGeek81 [ June 27th, 2005, 10:16 pm ]
Post subject:  re

Not too concerned with weight. I'd like to try vacuum bagging just to do it but I'm not going to bother with this. I may just make the form out of cardboard and glass in the cardboard (use it as a cheap foam core kinda) and then paint it so it looks decent.

I think I will make the lid first to get some ideas on the strength of this stuff. I can just lay out some plastic or wax paper, wet out a few layers of class and then cut to shape afterwards. I'll have a board of fiberglass more or less I can try bending and such.

Author:  Komatiq [ June 27th, 2005, 10:38 pm ]
Post subject:  stiffeners........

Cardboard would work as a core as long as it's fairly well sealed along the edge. A thin plywood or door skin works too.

If you want to stiffen a flat glass panel you can use a cardboard tube cut in half along the length. Lay it down in a stip of wet mat then glass over the top and out onto the panel an extra inch or two.

Vac bagging is a good method for cutting down weight but don't use the wife's vac :tsk: ........... she'll skin you alive.


Author:  GQGeek81 [ June 28th, 2005, 8:14 am ]
Post subject:  re

got a vacuum pump out of an old fridge. It will pull 30"Mg easy so it could handle this no problem.

I'll be playing around with that later when I start tinkering with paddles.

Author:  Komatiq [ June 28th, 2005, 10:58 am ]
Post subject:  Vac pumps

Never thought of a fridge pump......... may try to scare up one myself. Hard to get better than 30 Hg in our atmosphere.

I have seen vac pumps from milking machines used in the past and they had enough cfm for small bagging projects so a fridge pump might work great for smaller stuff.

Got spoiled working on big boats where we used 10 hp monster pumps with 120 cfm and 2" vac lines.

All the best with your seat/wanagin project.......


Author:  GQGeek81 [ June 28th, 2005, 2:18 pm ]
Post subject:  re

If you do a web search you can find the article, some guy made made the pump to vacuum bag his model airplane wings. I stole the idea for something else and retrofited the pump so its basicaly a stand alone appliance that I can use as either a compressor or vacuum pump. The only extra thing I'd really need for fabrication would be the epoxy trap.

Author:  Komatiq [ June 28th, 2005, 2:49 pm ]
Post subject:  Web search......

I'd be keen to look ito that further. Any hints as to what phrase you used in your search?

We made a few small resin traps from PVC tube with a solid end cap on one end and a screw off on the other. Ran the vac line through it and had an empty dog food can inside to catch any resin that was drawn in. Simple and worked great. Any plastic pipe should work OK as long as the walls have a reasonable thinkness.


Author:  Komatiq [ June 28th, 2005, 8:19 pm ]
Post subject: 

Hey GQ.......... found it !! Thanks for the tip.

Author:  GQGeek81 [ July 7th, 2005, 12:59 pm ]
Post subject:  re

Well I decided to go with a birch plywood core (cheapest suitable looking material I found at Lowes) and have cut out my pieces and am working on glassing it.

I started by experimenting with some glass and resin to see how stiff/strong two layes would be. It was pretty floppy but a layer of mat stiffened it up nicely. I took that piece and drew out a square and then added two inches to each side. I then cut out the shape with the table saw and bent all the sides in at the 2" line with a metal brake. When folded up I get my tray which will sit just inside the lid on top, cover half the opening and can be side back and forth or pulled out to get to the stuff underneath.

I had to add some additional glass in the corners on the inside of the tray and I'm going to go ahead and cover the mat side with another layer of E glass for the cosmetic effect but after just the pieces on the inside corners it was suprisingly sturdy. I loaded it down with some heavy wrenches and stuff from the shop and lifted it up and it didnt bend or wrap under the weight at all.

I'm going to add a layer of glass to the inside of the whole thing (maybe a few for the lid since it will hold alot of weight. and then mat then glass on the outside.

The inside of the lid/seat will have about a half dozen pieces of 5/16" wooden dowel rod glued along it and intervals and then glassed which should help stiffen it up.

The inside bottom will be dived by two pieces of glass so it makes three sections. I'm thinking I can use this as a full three step wash sink for the dishes (soap/bleach/rinse).

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