Ideas Needed for a conundrum

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Ideas Needed for a conundrum

Postby AutomatedMedic » Thu Jun 09, 2016 6:16 pm

So I'm just finishing up when the design phase of my build when I realized I had a problem. I plan on using a fiberglass skin and the Issue I'm going to run into is there will be areas of it that I would some how need to be able to apply my resin and cloth on a Vertical slope and a negative slope-sloped over head what ever you want to call it- in other spots. This will be my first run with playing with fiberglass and to my knowledge I thought you had to put it on a flat surface? Ideas on how to fix this??
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Re: Ideas Needed for a conundrum

Postby les45 » Thu Jun 09, 2016 6:41 pm

I used a fiberglass system on all my joints which involved quite a bit of vertical surface and even some reverse slope in the bottom bevels on my weekender. After wetting in the tape with a brush, I simply used a 4" foam roller for subsequent coats just like applying paint. I don't recall having any problems with the vertical surface although, admittedly, it wasn't an entire wall. And it was a bit messy with lots of dripping on the vertical areas so use drop cloth. Also, you have to use rollers that work on epoxy as regular paint rollers will disintegrate after a few minutes.

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Re: Ideas Needed for a conundrum

Postby KCStudly » Fri Jun 10, 2016 8:24 am

I did the walls of TPCE with 2 plies of 6oz cloth wetting thru both plies all at once, dry on dry on dry.

I tilted the cabin up a bit to the side so that it wasn't a dead vertical surface, started at the top at one end and worked my way down to the bottom in manageable sections . I did have some issues with runs. Because I was working in cool weather I used the fast hardener. As I started at the top invariably some slobbering would drip and/or run down the side beading on top of the weave and not really soaking in. If allowed to start to gel, by the time I worked into these areas, the runs would make it really hard to get the areas under them to wet thru. So for the remainder I would try harder to keep the runs in check. If I did get one I would chase that area and wet it thru, before going back up and starting another area from the top. I'm not sure if this would be an issue when working with the slow hardener in more mild temperatures.

Another issue I had was ripples forming in the first ply when squeegeeing thru the second ply. Research after the fact suggests that if I had wet out the wall, let it start to gel a little, then positioned the first ply and wet that out (which seemed like it would be very awkward to do neatly under the gun by myself), let it start to firm up, then repeat, and then keep going with neat epoxy in wet/let tack/wet/let tack layers until the weave was filled plus at least one coat, I probably wouldn't have had that problem (I have some ripples in the rear panel of my street side wall that I will have to sand down and/or fair in). As a beginner to the world of large FG projects, it has been a learning curve. Same thing with using fillers to fair areas to be covered with cloth; let them set up a bit before moving on to the cloth layup, otherwise it is easy to squeegee the filler into a lump under the cloth (the other option would be to let the fairing coat fully cure, wash amine and then sand it before moving on. Some people like to do a sealer coat with just neat epoxy/wash amine/sand to tooth and then do any fairing before getting onto the cloth; in hindsight I might have done it this way. If I was building an airplane or boat hull (both highly stressed structures) I would be a lot more concerned about achieving chemical bonds, but for my purposes I have not been disappointed by the mechanical laps I have done (and don't expect any problems in the future, either... this camper won't be doing any 3G pull ups or crashing rough seas.

It would have been preferred to do the whole wall in one large extended layup with at least one helper to stretch and place cloth over wet in stages (better yet to have a large enough work bench to wet the cloth out in the flat first then transfer to the wet wall... didn't have that). Although I can get help from friends, it adds a layer of complication and I just don't have the stamina or time required for the marathon all day plus layup sessions. So I broke the walls down into more manageable sections and planned out lap seams (front of wall ahead of side doors; over and under door opening; large rear section of wall). The roof was easily done in one session because gravity was working in my favor.

For manageable sized pieces in awkward or vertical positions, I found the PMPP (poor man's prepreg) technique to work well. Essentially you do the wet out onto a pattern drawn on a sheet of plastic; sandwich with another sheet of plastic; cut out your pattern (keeping the scissors cleaner and loose strands at bay); peel the top sheet of plastic; apply the wet out to the surface using the bottom sheet of plastic as a handling aid (it keeps the cloth from stretching out in all of the wrong directions and makes the process go with a lot less gooey-ness); squeegee it in place right thru the plastic; carefully peel the plastic off; and then just squeegee and daub down any areas that need a little extra help. There is a limit to the size that can be done practically, at least for me working alone, but it is a very efficient and useful technique.

Bottom line is you can do it, just take your time and think things thru. Read up on techniques and procedures. Like building campers, everyone seems to have different techniques and tips for achieving the same results, provided you adhere to the basic rules. Also, pick a smaller task and do that as a confidence building piece (I glassed my tongue box before moving on to the cabin, and had plenty of lessons learned there).

Worst thing that could happen is you get a blister or two (...or three or more), or a pucker void along an edge that didn't have enough of a radius for the glass strands to confirm to. So you have to drill and syringe in some neat, or sand thru and scab on a patch that needs a little extra fairing. There are no real disasters that can't be fixed with more effort, time and, yes, money for supplies.
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Re: Ideas Needed for a conundrum

Postby KCStudly » Fri Jun 10, 2016 8:31 am

Forgot to mention that the wrap under the edge of the floor was the worst part, epoxy dripping onto the cardboard drip catchers I laid down on the floor, running down the brush handle and my Tyvek arm guard/sleeves, etc., but it can be done.

One of the best tips I was given, from Atomic/Michael (of hydroplane boat racing fame) was to cut down your chip brushes to about 1/2 to 1/3 of there normal length. Makes the bristles stiffer for daubing and still carried plenty of wet from cup to surface. I use regular scissors or a small paper cutter (the side cutting cleaver/chopping block type) to cut my brushes down.
KC
My Build: The Poet Creek Express Hybrid Foamie

Poet Creek Or Bust
Engineering the TLAR way - "That Looks About Right"
TnTTT ORIGINAL 200A LANTERN CLUB = "The 200A Gang"
Green Lantern Corpsmen
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Re: Ideas Needed for a conundrum

Postby AutomatedMedic » Fri Jun 10, 2016 9:26 am

I now know why you have studly in your name :applause:

Next question on that whats the Poor mans prepreg?
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Re: Ideas Needed for a conundrum

Postby KCStudly » Fri Jun 10, 2016 10:02 am

KCStudly wrote:Essentially you do the wet out onto a pattern drawn on a sheet of plastic; sandwich with another sheet of plastic; cut out your pattern (keeping the scissors cleaner and loose strands at bay); peel the top sheet of plastic; apply the wet out to the surface using the bottom sheet of plastic as a handling aid (it keeps the cloth from stretching out in all of the wrong directions and makes the process go with a lot less gooey-ness); squeegee it in place right thru the plastic; carefully peel the plastic off; and then just squeegee and daub down any areas that need a little extra help. There is a limit to the size that can be done practically, at least for me working alone, but it is a very efficient and useful technique.


I don't have time at the moment to go find the entry in my build where I show it being done, but can add a link later.
KC
My Build: The Poet Creek Express Hybrid Foamie

Poet Creek Or Bust
Engineering the TLAR way - "That Looks About Right"
TnTTT ORIGINAL 200A LANTERN CLUB = "The 200A Gang"
Green Lantern Corpsmen
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