sanding/pre-coating inside

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83glt
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sanding/pre-coating inside

Post by 83glt »

I was just curious if anyone out there pre-coats the inside of their boats w/ epoxy before glassing? If so, what have the results been and is there any reason not to pre-coat the inside?

Also, how even does the inside surface have to be before glassing? Does the surface have to be perfectly level? I'm finding that because I used alternating strips on the bottom of the hull, WRC and sitka spruce in order to achieve a striped pattern, the denser spruce strips are raised slightly above the WRC strips. The joints of the planks are nice and tight and level, and there are very few gaps. It just seems that the center of the spruce strips are higher. I followed the advice in Canoecraft to leave some of the original surface of each plank when scraping, but now I find the WRC sands faster than the spruce. Is this a problem, and should I ensure a perfectly level surface before glassing? Or will the slight undulations have no effect on the glassing. I kind of like the look and feel of the undulations as they're only on the football area, so if I can leave them without concern I'd like to do that.
Thanks to all who respond!

jason
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Bassbug
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Post by Bassbug »

I precoat before I epoxy, with one coat of epoxy. I find that I can do a better job of glassing that way.

Undulations should not create a negative structural concern. The fiberglass will go with the waves nicely. It is up to you how even you want the surface. Likely, you will be the only one that will notice it.
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Juneaudave
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Post by Juneaudave »

I've both precoated one boat and did not on another...on the Rice Lake Skiff, I precoated because I couldn't find cloth wide enough and had to glass one side at a time. Precoating allowed me to work with smaller batches and assured a uniform finish. On a canoe, I think the results are mixed. Some do, some don't. If your joints are tight and you can warm your shop prior to epoxying, I don't think precoating is necessary. If your joints have gaps, or if you can't get the hull warm, precoating might be a better idea. Regardless, I've found the inside to be more prone to bubbles and floating of the fiberglass. You need to be diligent after squeeging to make sure the glass is next to the hull and that any bubbles that might occur are popped. This is especially true if the surface is not quite fair (like the raised surfaces you described in your post). All in all, you've had some experience with glassing the outside, you should have no problems here!!!! :applause I would suggest that you re-read some of the posts on glassing the inside. There are some really good tips on handling the fiberglass at the stems. That part is always a challenge for me and I always end up fussing way to much in that problem area....Have fun...Juneaudave
83glt
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Post by 83glt »

Thanks for the advice guys. I've just finished the initial sanding, so it's probably going to be a week or more until I can get to the fiberglassing... Enough time to consider my approach and weigh the options!

Juneau Dave, you mentioned warming the hull. My workshop is basically a 18' x 15' toolshed and there is no heat source (it's separate from my house). This wasn't a problem during the warm summer months. As fall is here and I live in cool Canada, I'm concerned that the cool temperatures are going to effect the results of the inside glassing and epoxying the trim. Do you have any suggestions on how I might heat a workshop this size? I was thinking of just a small space heater, but will that do the trick in keeping this size workshop at approx. room temperature? Any suggestions? Thanks!
jason
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Ed Houston
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Post by Ed Houston »

I did not pre-coat and had no real big issues, I did use and would recomend anyone to try a bubble roller to wet the cloth out and remove bubbles.
This is a link to West Marine site that shows the rollers, good luck

http://www.westmarine.com/webapp/wcs/st ... 65/11160/4

Ed
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Juneaudave
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Post by Juneaudave »

I think a small space heater should work ok.. The trick is to warm up the room and hull prior to glassing, then let the temps drop as you apply the epoxy. What you don't want is a situation where you are applying heat directly at the hull....take a look at the following post where I had a halogen light..very hot...hitting a localized spot on some trim..

http://www.bearmountainboats.com/phpbb2 ... outgassing

Best of luck!
83glt
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Post by 83glt »

Thanks for the advice. I was thinking about using a roller and I'll probably give it a try.

Juneau Dave, it's nice to see I'm not the only one with an "organized" workshop! I just have one question. If I heat the workshop to close to room temperature with a space heater, then turn it off to allow temps. to fall as I glass, will it be problematic if the temperature drops significantly over the course of the following 2-4 hours as the epoxy cures? I'm guessing that the air temperature in my tool shed, without heating, will be in the range of 40 to 50 degrees. Thanks for helping me out.

Jason
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Juneaudave
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Post by Juneaudave »

Check with your epoxy supplier for the temperature ranges. I'm guessing you should be ok but you may want keep the heater on low.
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mvettori
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Post by mvettori »

JuneauDave,

I wish I would have seen this post earlier. I fiberglassed the outside of my hull last week and ran into the same problem. I used two halogen lights to light up the working area, only to find out that I was actually heating the hull. I had bubbles all over the glass when I came back to check.

Mike
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Juneaudave
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Post by Juneaudave »

mvettori wrote:JuneauDave,

I wish I would have seen this post earlier. I fiberglassed the outside of my hull last week and ran into the same problem. I used two halogen lights to light up the working area, only to find out that I was actually heating the hull. I had bubbles all over the glass when I came back to check.

Mike
Ouch!!!! Did you find the bubbles in time to pop them? I used West on the canoe which set ups pretty quick. On the Rice Lake, I used MAS with slow hardener which I find has more open time and lets you correct those mistakes. Regardless, with bubbles, you need to keep watching well after you are done laying on the glass.

Just another thought on cool weather epoxy...you can warm the epoxy by keeping it inside or warming it in a water bath. That keeps it thinner. I've even tried the microwave method where you put premeasured quantities of hardener and epoxy in for 10 seconds. Don't ask why I did this...but I can attest it really makes the epoxy runny so it will soak in, and your wife will most certainly disown you! :embarassed
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mvettori
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Post by mvettori »

Unfortunately, I didn't! I used a hypodermc needle to fill them in where I could. I got most of them. I'm in the process of scraping/sanding them down now. I'm sure to hit the cloth in the process, but reading some other postings it sounds like I can rebound from that with some minor blemishes.

Mike
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