Making new GRP engine box - Wide radiuses on corners advice

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DHV90

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Hi guys,

My engine is sat in the middle of the saloon, between the two settees, and currently is enclosed in a clumsy wooden box that doubles as a table, the top comes away but to remove the sides you have to take out a load of screws and also remove the rest of the sole boards etc. Its all heavy, clumsy and old and diesel stained. Im rebuilding the bilge and sole supports at the moment so would like to install them and then build a new engine box to cover the engine and am after some advice -

Making a nice lightweight one piece box out of GRP will be easy, I want it to be one piece and lift off all together nice and easily for maintenance and servicing, but I am keen to get really wide soft looking radiuses on each corner and am interested in the best way to achieve this.

My original instinct was to build a wooden frame with some ply or honeycomb material across the flat surfaces then just laminate the lot, Is it best just to beef up the internal frame at the joints so I can sand a radius into the corners or is there a better way of doing this altogether? Want to avoid unnecessary bulk and weight where possible.

Thanks in advance
 
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Hi searj

I have done a lot of these kinds of jobs and a few on my project boat, i have near always used polyurethane foam boards, just insulation boards. If you double skin it then it will also provide insulation. It sand really easy so you will get a good radius for the corners.

A lot quicker aswell and cheaper than using wood frame etc


Wayne :)


Few things i made with the foam, shows how it can come out .

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Thats awesome thanks Wayne, sounds like a good solution. What do you use to join the pieces of foam together so it's strong enough to sand etc. before fibreglassing?

Sounds like a box made of flame retardant insulation, laminated on the outside and lined with some of that silver reflective heat stuff on the inside would work nicely, thanks for the idea!
 
searj said:
Thats awesome thanks Wayne, sounds like a good solution. What do you use to join the pieces of foam together so it's strong enough to sand etc. before fibreglassing?

Sounds like a box made of flame retardant insulation, laminated on the outside and lined with some of that silver reflective heat stuff on the inside would work nicely, thanks for the idea!
Click to expand...

I have used both a hot glue gun and resin. to hold while the resin sets just push nails through the corners to hold it together then remove once set before laminating. Hot glue sets while you hold it in a minute.

Oh yes use nails twice the foam thickness pushed in at alternate angles ;) holds real tight then.
 
Awesome, many thanks, had a look in B&Q today and they had the perfect stuff at a couple of quid for a sheet so should be able to build the whole box without spending more than £20, with the bonus of built in insulation. Great suggestion looking forwards to getting started. Sure this will come in useful for lots of future bits as well
 
searj said:
Awesome, many thanks, had a look in B&Q today and they had the perfect stuff at a couple of quid for a sheet so should be able to build the whole box without spending more than £20, with the bonus of built in insulation. Great suggestion looking forwards to getting started. Sure this will come in useful for lots of future bits as well
Click to expand...

Just fro futer info i get mine from a local insulation suppliers, they sell damaged sheets at half price so a 25mm thick is about £10 and a 50mm around £15. 100mm thick are good for making all sorts.

They are not to damaged, i lined most of my boat out with it as it generally a few edges missing which you can just cut out or squarer up.

Glad i could help out, enjoy ;)
 
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