Adhesives

[silvermansteve]

hello. i'm building a bare hull 34 inch ekos with twin drives. it will be my first boat build, i've done a few cars and a helicopter though. anyway, this boat will use mostly stock hardware including rudder, servo mount, struts, motor mounts, and esc mounts.

so:

1. which adhesives might i best use to fasten the servo mount, motor mounts, and esc mounts to the hull? ca? epoxy? both in combination?

2. the hull is pre-drilled. when i bolt on the transom hardware and drives (all stock), should i lay a bead of silicon adhesive between the edges of the holes on the outside of the hull and the attached hardware, to seal them?

3. i guess lining up the stuffing tubes and motor mounts is easy in this build -- just make them straight -- right?

4. if i don't use the venom esc mounts, i can just stick the escs in where i want them with servo tape, or velcro tape, correct? i mean, why not?

5. when i'm done, had i best coat the entire inside transom with epoxy to make it water tight?

if there's anything else anyone wants to tell me about this, that's great. i feel like i barely know what i'm doing....

thanks!

steve

[Remmie81]

Hi Steve

1: I would use epoxy. CA is not strong enough. You can quickly tag the mounts to there position with CA but after that I would suggest to use epoxy

2: Yes you can, please make sure that you dont use 2 much Silicon. (note, please be aware that if you have Silicon on the transom and would like to paint it at a later time the Silicon will prevent the paint from sticking to the hull.)

3: You probable end up with slight bends in the stuffing tube as the engines are mounted higher then the drives are.

4: Using velcro is a good way of keeping the ESC in place.

Grtz,
Remmie

[silvermansteve]

thank you

[siberianhusky]

I've been using JB Weld epoxy for mounting motors and installing stuffing tubes, changed over from regular slow cure epoxy a few boats ago.
Mono caulking is perfect for sealing hardware holes, cleans up with soap and water and no future paint problems.
You will need to bend the stuffing tube, some people fill them with salt before bending so they don't crush. I don't usually but I've bent many over the years and have the feel for bending "free" by hand. You can also heat the area to be bent to anneal the tubing a bit.
Cheapest place I've found the good industrial velcro is Home Depot, can get it in black or white. The industrial stuff has some serious glue on the back!
I mount the motor after the stuffing tube is in place, I find it easier to make minor alignment adjustments with the motor than the tube.
I use a drop of CA to hold the motor in place until I've got the tube 99% right, glue the tube in then the motor.
Goop is a great adhesive for gluing in antennae mounts, and the rubber boots the pushrod goes through etc. can be peeled off when you need to replace things.
If you can swing the price of a West System epoxy kit this will cover all your epoxy needs from reinforcing with glass or carbon cloth, to waterproofing wood parts, to bonding. It can be mixed with a number of different thickening agents so it can be used for filler for repairs as well. In the long run it's cheaper than buying little bottles from the hobbyshop, bit pricey up front though. I've never seen anything about a shelf life, generally lasts me a couple years and I build a lot, always have at least one under construction (3 at the moment and still working on plans for a new hydro!)

[silvermansteve]

thank you too siberian you have given much to think about and i will refer back to these posts when i start. waiting on one more shipment of parts, well maybe two.

one of the things i must consider, is whether to reinforce the ekos hull with carbon fiber sheeting. i wasn't going to do it, as i imagine it's easy to do a SLOPPY job the first time, at least. but is not doing this a mistake, do you all think? and briefly, what's involved? is it: 1. cutting the sheet to fit, 2. then laying epoxy on the inside of the hull, and 3. putting the fiber sheets on top of the epoxy, smoothing them out? is it that simple?

thank you.

steve

[Fluid]

Do not use carbon fiber sheeting, use carbon fiber cloth (perhaps that is what you meant). Also, don't use regular epoxy to glue it down. Use either finishing resin (epoxy) or thinned regular slow-set epoxy with 25% isopropyl alcohol. This allows you to brush a coat on the surface you want the carbon to reinforce, lay down the cloth, then paint over the cloth (all at the same time). The thinner epoxy soaks into the cloth for a much better job.



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[silvermansteve]

thanks fluid. i probably meant carbon fiber cloth, yes. i already have the finishing resin. i might do this.

so i guess the idea is to get it on the bottom of the hull AND up the sides, right? i'd use one sheet and bend it to go up the sides?

[Fluid]

The most critical part is the top of the tunnel. This part flexes more than most of the rest of the hull does and should be stiffened. The shape of the rest of the hull adds stiffness. If you are worried about the top and bottom of the hull separating at the seam - a real concern wth some boats - then run a strip or glass cloth along the inside of the seam as far as you can. There is nothing wrong with putting cloth over all the inside surfaces, but it shouldn't be done in one step as it is almost impossible to do a neat job that way.



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[silvermansteve]

carbon cloth like this?

http://www.ebay.com/itm/GENUINE-CARBON-FIBER-Cloth-plain-weave-Fibre-/220998988671?hash=item337490f37f&item=220998988671&pt=LH_DefaultDomain_100&vxp=mtr#ht_500wt_1287

and thanks, fluid, i might well just do the top of the tunnel, then.

[siberianhusky]

Last one I did I laid out the cloth cut to size on a piece of glass with saran wrap stretched over it, poured some resin on it and used a home made wooden roller to wet out the cloth and roll out the excess resin.
Placed it inside the hull (was a cat) and used the roller again to smooth it out.
Looks almost like it was done at the factory, and I pretty much suck at fiberglassing!
To be on the safe side I wrapped the boat in a plastic bag and taped it around the hatch opening to keep from getting resin over the rest of the boat, woohoo no fingerprints this time!
You want just enough resin in the cloth to wet it out and bond to the hull, excess resin adds weight without a lot of strength. Give the inside a good scuff sanding and wipe it down with alcohol to give a good surface to bond to.
Not really that hard, lol you just have to commit to doing it, have everything ready before hand and go for it.
The west system epoxy is really easy to work with for laminating, not to thick not to thin and a long enough pot life that you can kind of take your time. Most of the bottled hobby shop epoxy is to thick unless they have what is called finishing resin, it's designed for this application. But not so good for actually gluing things together.
LOL after you buy all the different kinds of epoxy you can see why I switched to a type that will do everything!

[BrianW]

I have been using a product from 3M called DP-100 2 part Epoxy Adhesive. Its clear and comes in a 50ml tube. I use it with their Applicator with a small static mixer. No Mess or mixing!

[Remmie81]

Step 1: Clean the hull very good (use brakecleaner to remove all grease (even from fingers) etc)
Step 2: Sand the area you want to put the carbon on (it needs to be rough to have a good bonding with the epoxy)
Step 3: Do again step 1
Step 4: Cover everything you dont want to laminate (outside of the hull for example ;-) )
Step 5: Use a piece of rope to measure the length and Width you need for the Carbon Cloth. This is especially usefull for measuring the width of the tunnel as the rope can follow the curves of the hul. Make sure you measure above the seem of the hull.
Step 6: Cut out the piece of Carbon, make sure you dont twist the cloth (try to move it around as carefull as possible. Pretend its from glass)
Step 7: Prepare everything: Use hand protection, (a mask if you want).

(please note: everybody has an Allergy for Epoxy, except that its not active by everybody. The more you use epoxy with bare hands, the more you can activate the Allergy. Ones you have it, you will not be able to get rid of it. It will cause itchy and dry hands

Step 8: Make sure you have 2 paintbrushes (I prefer a round one and a flat one) a Foam roller , mixing cup, Epoxy , old clean cloth.
Step 9: Mix the Epoxy with the Hardner (have a good look of the prefered mixture and dont change that! and watch for the "Potlife" eg. how much time before the Epoxy begin to thicken and you cant work with it anymore)
Step 10: apply a thin layer of epoxy on in the hull with the Flat paintbrush
Step 11: Put down the Carbon from the middle of the tunnel. Then roll it out to the left and right. When you roll it out, try to push it carefully into shape with the hull.
Step 12: From the middle to the sides, use the round brush (put it in the epoxy) and then stamp with it on the cloth.
This way you push the epoxy into the cloth. Its stupid work, but it works better then "painting" the cloth.

Do this for the whole cloth. If you see anything shine (puddle of epoxy) go over it with the foamroller. This will suck up the to much resin.
Run the roller over the hole cloth. Incase the roller is to full, roll it out over the Old clean cloth that you have laying beside you (Step 8 )

Now let it all dry. Check every 10 min (for totall of 1 hour after you have finished) if the cloth is still laying correctly, if not push carefully with a brush.

If you have a lot of epoxy over and its still in the mixing cup, please be carefull as this can get very hot.

With my description above, this is the result I get:
From this:


To this:

[silvermansteve]

wow remmie, thanks! i'll review your detailed steps with care. so thanks very much. that is a lot to sit down and write, especially for someone you don't know. all the best to you there in the Netherlands (i think that's where....).

[Mel279]

Remmie

That's very informative, thanks a lot for sharing your experience

[Remmie81]

Thanks guys!

@Steve,
Youre right, im from The Netherlands


Remember I made a time-laps movie when doing a Alutex laminate in a friends MHZ Cayman

Just for you to get an idea.
When you see people moving but nothing happening, everybody was looking for the scissor

Good tip is were you see me rolling up the cloth from both sides and how I place it in the boat.