| Epoxy Additives for beam seating. #102710 04/03/07 04:08 PM 04/03/07 04:08 PM |
Joined: Aug 2005 Posts: 2,921 Michigan PTP OP
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Posts: 2,921 Michigan | Lets say you were going to compensate for a minor diameter difference when seating a beam (like OD of the beam 4inches and mounting onto a fraction of a tube - flipped inside out with an ID of 3.75 inches) and you were going to use epoxy to make up the difference. Would you use just straight west system epoxy? Would you use structural filler (high density 404)? Other filler? Chopped glass/chopped glass matte?
p.s. forgive me for posting something having to do with sailing... or working on cats.... mea cupla <img src="http://www.catsailor.com/forums/images/graemlins/laugh.gif" alt="" />
PPS.. I just reread Jake's Teamseacats.com blog and saw how he did it last year prior to the Tybee. Jake... what was the type of mold release you used? where did you get it? And how do you not get epoxy into the bolt holes? When you tighten down the bolts don't you epoxy the bolts into the nuts?
Last edited by PTP; 04/03/07 04:19 PM.
| | | Re: Epoxy Additives for beam seating.
[Re: PTP]
#102713 04/03/07 06:59 PM 04/03/07 06:59 PM |
Joined: Nov 2005 Posts: 337 Victoria, Australia C2 Mike
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Posts: 337 Victoria, Australia | Lets say you were going to compensate for a minor diameter difference when seating a beam (like OD of the beam 4inches and mounting onto a fraction of a tube - flipped inside out with an ID of 3.75 inches) and you were going to Just for clarity, are you wanting to make it a permanent joint or still so you can get the beam off later? Tiger Mike | | | Re: Epoxy Additives for beam seating.
[Re: PTP]
#102714 04/03/07 07:03 PM 04/03/07 07:03 PM |
Joined: Jun 2001 Posts: 12,310 South Carolina Jake
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Posts: 12,310 South Carolina | Any good carnuba wax will work as a mold release...although your comfort level will certainly go up if you get a wax specifically made to be used as a release. I used milled glass fibers for the filler because it really sets rock hard (chip it with a hammer like). Coloidal silica will work fine too - micro balloons might be a bit soft and not resistant to abrasion (if there is a little wiggle). I kept the resin out of the bolt holes by putting a clay ring around the holes and a clay dam at the ends. That first-grade silly putty snake making method has come in handy once again.
Jake Kohl | | | Re: Epoxy Additives for beam seating.
[Re: ncik]
#102715 04/03/07 07:30 PM 04/03/07 07:30 PM |
Joined: Aug 2005 Posts: 2,921 Michigan PTP OP
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Posts: 2,921 Michigan | Depends on how big the difference in diameter is as to the preferred solution.
If it's small, just put some brown packing tape on the beam for simple mould release (make sure it's a smooth surface, overlap of the tape is fine though) and squash beam straight onto the mounting with glue between. Pop beam off and clean up the bog (as suggested, colloidal silica or microfibres; not fairing or lightweight filler additives).
If the gap between beam and mount is big, might be best to mould a fibreglass mount around the beam first and then glue that in-place to take some of the bearing stresses out of the cured bog, otherwise it might crack.
A big gap might be larger than 5mm. Any bigger than this and the filler might start to crack when the boat flexes.
Make sure when you redo the mounts that the boat will be aligned correctly once it's bolted up. Will putting chopped glass in the resin mix make it less likely to crack under stress? Is there a problem with using the chopped glass and 404 filler in the same mix? The putty rings would work well I think. I aim to keep it so that the beams can still be removed, although I guess it doesn't matter too much. | | | Re: Epoxy Additives for beam seating.
[Re: PTP]
#102716 04/03/07 09:19 PM 04/03/07 09:19 PM |
Joined: Jun 2001 Posts: 12,310 South Carolina Jake
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Posts: 12,310 South Carolina | I don't think you could go wrong with either one or mixing...although I don't know what advantage you would get by mixing.
With "mold release wax" (some real generic stuff I got from US Composites), the beams popped loose from the hulls with just a slight bump from underneath with a rubber mallet.
Jake Kohl | | | Re: Epoxy Additives for beam seating.
[Re: PTP]
#102718 04/04/07 02:41 AM 04/04/07 02:41 AM |
Joined: Jul 2006 Posts: 461 Victoria, Oztralia mattaipan
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Posts: 461 Victoria, Oztralia | Hi All
When seating in my beams I mixed West System with microsphere blend and a little glue additive as well. The beams where they would contact the mix were covered neatly with brown package tape and coated with a polymer car polish as well.
The tape covered the beam holes and left a small ring showing when the beams were popped out, so I could drill the holes either while the beams were on or off, which was handy for the inside rear beam holes, because the bolt doesn't go all the way through the beam.
It only took a light tap out with a rubber mallet and left a very neat and clean beam pad <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" />
Matt Harper
Homebuilt Taipan 4.9
AUS 329 'GOT WOOD' SEEDY PIRATES RACING TEAM
| | | Re: Epoxy Additives for beam seating.
[Re: Dan_Delave]
#102720 04/04/07 10:57 AM 04/04/07 10:57 AM |
Joined: Jun 2001 Posts: 12,310 South Carolina Jake
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Posts: 12,310 South Carolina | yes, sand the socket with 80 grit. However, I'm not a big fan of adding catalyst after mixing in the filler - I get worried that you won't get a good mix (and have had issues with that before). In the case of epoxy, you are adding at least 1/3 as much hardener so even if you mix up to the thickness you want, it's going to get diluted with the 2nd part of the mix.
Jake Kohl | | | Re: Epoxy Additives for beam seating.
[Re: Jake]
#102721 04/04/07 11:34 AM 04/04/07 11:34 AM |
Joined: Dec 2001 Posts: 5,590 Naples, FL waterbug_wpb
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Posts: 5,590 Naples, FL | Would styrene be good to wipe on the surface of the hull first to assist with the epoxy bonding. The surface is gelcoat, right?
Jay
| | | Re: Epoxy Additives for beam seating.
[Re: waterbug_wpb]
#102722 04/04/07 01:11 PM 04/04/07 01:11 PM |
Joined: Jun 2001 Posts: 12,310 South Carolina Jake
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Posts: 12,310 South Carolina | I think acetone is a better de-greaser, more readily available, and slightly less hazardous to your health than styrene (which melts soft tissue).
Jake Kohl | | | Re: Epoxy Additives for beam seating.
[Re: MauganN20]
#102724 04/04/07 01:33 PM 04/04/07 01:33 PM |
Joined: Jun 2001 Posts: 12,310 South Carolina Jake
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Posts: 12,310 South Carolina | oh c'mon Jake, where's your sense of adventure? :P
Plus, styrene would make a better how-to video on youtube. Yeah, but who's going to agree to be scoped so the video of the lung tissue melting could be had?
Jake Kohl | | | Re: Epoxy Additives for beam seating.
[Re: PTP]
#102725 04/04/07 04:12 PM 04/04/07 04:12 PM |
Joined: Jun 2002 Posts: 1,658 Florida Suncoast, Dunedin Caus... catman
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Posts: 1,658 Florida Suncoast, Dunedin Caus... | If I read this right the fill will be about a .25". I would make sure there is mill fiber in the mix if your making your own putty, or use a structural filler. I have no experience with 404 so I can't comment on it.
If your making your own putty then I would add mill fiber to the resin until its thickens but can still be easily poured. Then add the hardener,mix well and then add the silica to thicken to the consistency you want. Mill fiber adds tensile strenght to the resin. Important to prevent cracking of the putty.
Jake, did you do one saddle at a time or all four at once?
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