Fiberglass work

Discussion in 'Darkroom Equipment' started by raucousimages, Sep 1, 2006.

  1. raucousimages

    raucousimages Member

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    I am posting under "Darkroom" because the same info would apply to a fiberglass sink. I have built fiberglass over wood sinks in the past with no problems but I just built several water/dust proof boxes to take film holders to the field with a fiberglass lining. The problem is that after 4 days to cure I still have some spots with a sticky film. I don't think the resin and hardener were mixed well. The bulk of the resin is solid just sticky on the surface.

    Can I clean up the uncured resin with acetone with damageing the hard resin or is there a better solution?

    Thanks John
     
  2. JLP

    JLP Subscriber

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    John,

    Having some fibreglass experience from the past i would suggest some local heat to those spots. Eventually it should harden but a hairdryer or other heatsource for an hour should speed up the hardening process.
    (Don't set anything on fire though)


    jan
     
  3. raucousimages

    raucousimages Member

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    A heat lamp and 4 days in the hot sun have not worked. I still have a few sticky spots. I will try the hair dryer or even the oven. I have cured epoxy in an oven. Just pre heat to 200f, turn off and place parts inside for a couple of hours. The acetone is tempting but too much time went into the boxes to ruin them with chemicals and it was the last of my oak.
     
  4. Robert Hall

    Robert Hall Subscriber

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    I had a couple spots on my old sink. They stayed tacky for almost a year. What has happened is that the resin was too thin to harden. It needs critical mass of about a millimeter to harden. (sure the chems may also have not been mixed well either.) I would get out the acetone and wipe it down, then get out some 120 grit and give it a good sanding (with a mask on) wipe them off and give it another coat that is a little heavier. I had to do it on level surfaces for the sinks, as you will see when you stop by, and rotate the sinks to do each side while flat. A pain, for sure. After 24' of sink, I think I got it down. At least I think I do. :smile: I do hope never to have to do that again.
     
  5. rexp

    rexp Member

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    From my experience in a body shop, I would say acetone or lacquer thinner would either be OK. I have removed lots of paint from Corvettes using acetone, and often wiped down raw fiberglass with lacquer thinner to remove any oils (seems I was the one who got the least itchy working fiberglass, and was then by default the 'glass expert). If you are hesitant, I suggest you try a small spot on the inside where it can't be easily seen.

    Put your smokes out first, acetone has a low flash point.

    rexp
     
  6. raucousimages

    raucousimages Member

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    A quick wipe with acetone and an hour in a warm oven did it.

    Thanks, John
     
  7. donbga

    donbga Member

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    I would have to ask why go to all the trouble and expense to build a fiberglass box for film holders to reduce dust and water when you can purchase soft insulated lunch pouches for practically nothing. Just put your holders in sealable poly bags used for freezing foods and put that in the lunch pouch.

    Be sure to wipe the face of the darkslide off with an anti-static cloth before loading it into the camera. Keep your bellows clean.
     
  8. raucousimages

    raucousimages Member

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    I had some holders damaged when my toolbox shifted in the back of the truck and smashed the soft lunch box I had them in. And I had some strips of oak ply in the garage so I thought I would make some hard boxes for the holders. My gear takes a real beating on the roads I travel so I do every thing I can to protect it. My cameras are in Pelican cases and every thing rides on a futon mattress in the truck to absorb shock. It really sucked to lose some old Lisco wood holders to a tool box. Never leave nice wood around an old carpenter, something is going to get built.
     
  9. leeturner

    leeturner Subscriber

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    I used to spend weekends working with a friend who had a composite business specialising in carbon fibre parts for racing cars and bikes. Only once did we have a resin problem and that was when the mix ratio was incorrect. In that case the part took six days to harden. There are three types of resin; polyester, epoxy and phenolic. The epoxy is particularly sensitive to mix ratios and temperature. If the temperature was too low an accelerator had to used to restore the curing time to normal. In commercial applications a vacuum autoclave is used to effect consistent curing and forming,usually in conjunction with preimpregnated composite sheets.

    For uses such as darkroom sinks the cheaper phenolic resin is a good choice. It's the standard in aircraft for items such as overhead bins as it doesn't produce toxin fumes if burnt and it's pretty resistant to chemicals.
     
    Last edited by a moderator: Sep 2, 2006
  10. Phil

    Phil Member

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    John,

    I have used West System epoxy for many small projects, and know others who use it for much larger ones. They have a great web site with a user manual and problem solver guide containing information that may be helpful.

    http://www.westsystem.com/frames/tier1/usingepoxy.htm
    http://www.westsystem.com/frames/tier2/usingepoxy/problemsolverguide.htm

    A canoe builder friend in Maine told me people would overlook his canoes at outdoor sports shows to check out his fiberglassed pack boxes!

    http://gilgilpatrick.com/outdoor-gear.html

    Phil
     
  11. noseoil

    noseoil Member

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    Another type of box for film holders. The surplus ammo cans (metal, gasket sealing lid) will not crush. You would need a liner for the metal to protect holders, but they are bullet proof, water proof, available and cheap. Just wouldn't want to lug them around out in the field. tim
     
  12. raucousimages

    raucousimages Member

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    Most of my ammo cans are full of ammo. I shoot more than just cameras.

    I think the problem was mixing the resin and hardener. This was an old fiber glass kit to repair garden ponds and fountains. Just mix the tube of hardener into the bottle of resin and shake. I don't think I mixed long enough and the bottle had a coating of resin without enough hardener that poured out as the last few ounces. I poured into the first box and coated it then dumped into the second and so on. The boxes got better down the line with the last being the best. So I think by the last box it was well mixed.

    The idea is to use the boxes to store the holders safe at home and to transport them in the truck then transfer a few to the pack in the field.

    I have read of old methods of water proofing like mixing pine tar, boiled linseed oil and turpentine into a thick paste and coating the inside of a box or tightly woven basket then dropping in red hot rocks and rolling them around. The rocks work the mess into the cracks and evaporate the turpentine leaving the rest firm. As the linseed oil evaporates the pine tar hardens waterproof. I think I like modern resins.
     
  13. graymatterimages

    graymatterimages Member

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    John, If you used a polyester resin it is in its nature to remain sticky. The typical procedure is to ad a few drops of liquid wax ( you can buy it from fiberglast) to the last layer. Just a few drops in the mixing cup stirring well before you apply. OTOH a good epoxy resin will dry without the stickyness.
     
  14. donbga

    donbga Member

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    Putting the soft lunch boxes inside an Igloo cooler will solve that problem.
     
  15. raucousimages

    raucousimages Member

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    I use a Coleman cooler on wheels for 8X10 holders. I dont like them for 4X5 due to the size and the plastic collects dust. By the time I pack for a long weekend out (2 adults, 3 children, 1 8x10, 3-5 4x5s, film holders, Hassy, RZ67, a couple of 35s 5-7 tripods +food, packs, stove, tents, sleeping bags with pads, tools, shovels, axe, high lift jacks, an extra spare tire and one beagle) space is an issue.

    I liked the idea of a hard box the exact size ineeded for my holders.
     
  16. raucousimages

    raucousimages Member

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    Yes that was an EXTRA spare tire. I always carry two after shredding a tire in the Silver Island mountains north of the Bonneville Salt Flats. Changed the tire and destroyed the spare less than 100 yards later on sharp lava. 20+ miles back to Wendover on the rim to buy a used tire for $50.00 then limp back to Salt Lake. I am hard on tires but it gets me away from crowds.
     
  17. DBP

    DBP Member

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    You may be the first civilian I've heard of who actually needs a HMMWV. Do the civilian ones have run-flat tires?
     
  18. raucousimages

    raucousimages Member

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    I now drive a Jeep and a Dodge 1 ton truck but I was in the Marines when they introduced the Hummer. They took away my beloved M151-A1 Jeep and gave me a Hummer. It is a great vehicle but I hated driving it. I would not own one but yes you can order a civilian version of the original hummer with run flats and the on-board compressor but it was only about $500.00 to add a second spare on the truck. Besides I can rotate six tires, it gives me a long life on a set.
    [​IMG]

    This is my truck after a few days photographing trains and wild horses in Ely, NV.
     
  19. Pragmatist

    Pragmatist Member

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    The solution is...

    MEK. Yes, the very same hardner you used in the initial resin mix. Brush liberally over the soft areas. Some reapplication may be necessary over the course of the day. This will leave an oily residue that may be cleaned up with acetone.

    A word of caution---some of the fiberglass resins use a carnuba wax that floats to the surface. Lightly sand prior to application. Also, if you have used a colorant, you may wish to prepare another resin/colorant/hardner mix over the spots you have treated. As before, sand beforehand. This method also works to seal soft or thin spots on the surface (ones that wont harden, or having some exposed glass mat).