Glassing in new engine mounts

[Guest]

Hi
As a complete novice to this area of boat work can anyone point me in a good direction as to what materials i need and how to prepare the hull/bilge area for glassing in new/adaptive engine mounts. ie do i need to rough up or treat in some way the existing surfaces? Do you need to paint the bilge/interior hull surface and if so what would you recomend?

Any info / help warmly received.

Rgds
Kev

 

[deejames]

There's no quick and easy answer to your question, but based on doing this job twice, here's my ten-pennorth .......
1. Yes - to get a good bond between any new glassfibre and the original hull, you'll need to roughen up a considerable area around where the bearers are going to be installed. Use an angle grinder (carefully) and wear a dust mask.
2. Make a "mockup" of your engine out of plywood or MDF and some dowel etc. You need a means whereby you can establish where the base of the engine mountings will be in relation to the prop shaft, the available space etc.
3 There are many different ways of securing the engine mountings to the bearers - you can glass-in a steel bar which can then be tapped for bolts, you can position the bearers in such a way that steel angle can be bolted to the bearers, or (and this is IMHO the easist way) - make the bearers out of a good hardwood (iroko) - glass them in with lots of layers of CSM and then use coach screws to secure the engine feet to the bearers.
4 Depending on how bored you are by this stage, you can spend ages getting a really smooth surface on all the new glassfibre, and then paint with a 2-part gloss enamel, or you can spend less time on getting a reasonable finish, and then use a bilge paint to finish.
5. If you can afford it, and have the space, I can recommend an Aquadrive shaft coupling. It takes a lot of the anxiety out of exact engine alignment, and it also cuts down a lot on noise and vibration.
I'm sure that others may have different views, but I guess the key thing is to make sure that your engine is well supported, and that it won't fall off the bearers if the going gets rough, that the bearers are well bonded to the rest of the hull so they won't fall over if the going gets rough, and that the engine is properly aligned in all directions with the prop shaft.

deejames

 

[oldsaltoz]

Hi KevD
A little more detail would help but the basics are as follows.
Make sure you have good ventilation and protection; Goggles, facemask ear plugs and so on.
(1) Remove all contamination, oil, grease etc or it will contaminate the new surface when grinding.
(2) Remove any paint within 8 inches of the mount by grinding with a small (say 4 inch) grinder, check your local tool supplier for a concrete grinding disk and purchase 2 of them. Remove all paint in the area to be glassed and clean up without wiping over the area you have just ground, wipe this with a solvent if you must.
(3) Lay out the engine mounts and pre cut the fibreglass mat to the required shape, you will the first piece to be at least 6 inches larger than the mounting all round; you will find it easy if you put the largest piece on first, each following piece should be smaller so the glass is tapered, this will prevent hard spots. Do not lay more than 4 layers at one time, as this will generate a lot of heat. Use only epoxy resins, as this will provide a very good bond.
(4) Put on some rubber gloves, the surgical ones are best. Paint a coat of resin on and lay the first sheet of glass, place the glass and add more resin, using a very small diameter roller (available from your resin supplier) roll the excess resin out till all dry or white areas ere wet, apply the next layer wet on wet and add resin, roll it out again, repeat this for 4 layers then stop. Let this go off and if you need more use the second un contaminated grinding disc to clean it up, apple glass as required and let it go off.
(5) When you have enough glass on, give the whole thing a wash in plain water, use an abrasive pad (one of those little green squares used on the dishes is fine) to remove the thin layer left by the resin reaction then sand any sharps off.
(6) Give the area a good layer of ‘flow coat’, applied with a brush.
A visit to the site listed below should give you some good pointers also
http://www.atlcomposites.com/west_system.htm
Avaniceday Old Salt Oz.