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Epoxy Additives for beam seating. #102710
04/03/07 04:08 PM
04/03/07 04:08 PM
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PTP Offline OP
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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.
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Re: Epoxy Additives for beam seating. [Re: PTP] #102711
04/03/07 04:44 PM
04/03/07 04:44 PM
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Dan_Delave Offline
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I use Coloidal Silica that West Systems sells. Mix it to a none dripping paste. Works great. Make more than you think you need.

Later,
Dan

Re: Epoxy Additives for beam seating. [Re: PTP] #102712
04/03/07 06:43 PM
04/03/07 06:43 PM
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Brisbane, Queensland, Australi...
ncik Offline
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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.

Re: Epoxy Additives for beam seating. [Re: PTP] #102713
04/03/07 06:59 PM
04/03/07 06:59 PM
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Victoria, Australia
C2 Mike Offline
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Quote
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
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Jake Offline
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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.

[Linked Image]

[Linked Image]


Jake Kohl
Re: Epoxy Additives for beam seating. [Re: ncik] #102715
04/03/07 07:30 PM
04/03/07 07:30 PM
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Quote
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
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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] #102717
04/03/07 10:56 PM
04/03/07 10:56 PM
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Brisbane, Queensland, Australi...
ncik Offline
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Chopped fibres may reduce the chance of cracking. I'm not familiar with 404, generally only use microfibres (which are small versions of chopped fibres). I wouldn't expect it to be a problem mixing 404 with chopped fibres, hell the purpose of the additives is to join/fill/fair fibreglass products, adding fibres to it shouldn't be a problem. You won't be able to add too much choppy anyway because choppy bog gets very hard to mix after a certain amount.

Any cracking/chipping would only be on sharp edges and would probably only be a concern with regard to appearance, not the structure of the mount.

Re: Epoxy Additives for beam seating. [Re: PTP] #102718
04/04/07 02:41 AM
04/04/07 02:41 AM
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Victoria, Oztralia
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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: mattaipan] #102719
04/04/07 09:51 AM
04/04/07 09:51 AM
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For releasing the beam most paste waxes will do. I do prefer a mold release wax, but I have done a lot of mold making and have it on hand. Put the wax on with many layers. I do not put on less than three, but I usually do about 7. Rub the wax on, thinly, let is sit until it starts to dry a bit, then with a soft rag polish it like you would a nice piece of furniture. It will seem as though you are wiping off all the wax you put on but continue this process 7 times if you are patient. It should only take about 10 minutes to complete each layer if it is not raining out. Just have other things to do one or near the boat so you do not rush it too much.

When Mixing the Epoxy with the Silica or MicroFibers leave the hardener out until the end. I do not recommend balloons or too coarsely chopped glass, you need to make sure it will flow and you want something tough. Get the consistancy you like before adding the hardener. It will thin a bit when you do add it.

I put the material in the hull saddle thickest at the bottom and spread it onto the whole area so I am sure there will be connection with the boat. I score the area well with a pick or something that will scratch the surface pretty aggressively. While you insert the crossbar and bolt it down the thickness at the bottom will find its way around the crossbar and ooze out the top and sides. Get ready to scoop this up with something appropriate. Cinch the crossbar down as tight as you would if you were sailing the boat.

Things to consider:

Tape some paper to the sides of the boat under where you are working. This stuff will try to make a mess of things, if you let it.

Make sure you do not trap the crossbar. If you see that filling in the gap completely covers more than 1/2 the bar you can imagine that getting it out will be hard. While working on an Infusion I recognized that this would happen so we were careful to leave an exit for it.

With the right preparation the crossbar with pop right out with a slight tap. I usually can use the palm of my hand and slips right out. If you do not need to take it apart leave it and know that it will come out when you need it. Sometime while sailing you may hear a thud...that may be the bar releasing from the hull.

Later,
Dan

Re: Epoxy Additives for beam seating. [Re: Dan_Delave] #102720
04/04/07 10:57 AM
04/04/07 10:57 AM
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Jake Offline
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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
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waterbug_wpb Offline
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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
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Jake Offline
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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: Jake] #102723
04/04/07 01:25 PM
04/04/07 01:25 PM
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oh c'mon Jake, where's your sense of adventure? :P

Plus, styrene would make a better how-to video on youtube.

Re: Epoxy Additives for beam seating. [Re: MauganN20] #102724
04/04/07 01:33 PM
04/04/07 01:33 PM
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Jake Offline
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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
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Florida Suncoast, Dunedin Caus...
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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?


Have Fun
Re: Epoxy Additives for beam seating. [Re: PTP] #102726
04/04/07 06:27 PM
04/04/07 06:27 PM
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I've used west system, mixing resin and hardner first, then adding Maas brand milled fibers and colloidal silica until it is fairly thick viscous liquid - not soft peaks or peanut butter (too dry).

I use a couple of coats of Nufinish (cheap teflon wax available from wally world for less than five bucks) as mold release. Dan's wax technique is probably better, but life is short <img src="http://www.catsailor.com/forums/images/graemlins/wink.gif" alt="" />

The sockets get a good clean (wire brushing sometimes) followed by some 60 or 80 grit to key them up, a bit of cross hatching with a screw driver then a wipe with denatured alcohol.

Then I mix up the goo, slap it in, on with the beams and snug the bolts tight while mopping up the excess (the more times you do this the better you get at estimating how much you need to put in the sockets).

Jakes idea with the silly putty makes sense. I've just mixed the goo a bit thicker and avoided the bolt holes and have yet to have a permanently bonded boat (but your mileage may vary).

Chris.


Dave Ingram is my president. tcdyc rules
Re: Epoxy Additives for beam seating. [Re: flumpmaster] #102727
04/04/07 06:40 PM
04/04/07 06:40 PM
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do people do this with the boat on the trailer so that the boat is square or do you do it on the ground... and how do you measure to make sure it is square?


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