Bonding in consoles

BruceB · 30 April 2008, 19:22

I am looking at fixing in my new console and for various reasons am considering bonding it in. Assume I know nothing about working with Glassfibre (not very far from the truth), how would I do this and what would I need to make a good job of it?

jwalker · 30 April 2008, 20:14

Just be aware that ultimately the bond between your consol and the boat will be the fibreglass cladding to plywood deck surface and fibreglass to wood is not always the best bond. The fibreglass cladding will only be about 2mm thick and you will need to take some of that back in your preparation.

Hightower · 30 April 2008, 21:12

Bonding is good, but I would also use a mechanical way of securing too, like using ss wood screws and penny washers

BruceB · 30 April 2008, 21:30

I looked at fixing in my console and am a bit worried at the sides that I will end up puncturing the outer hull with the fixing screws, the console is the full width of the inner space.
I was considering grinding off the external fixing flange on both sides and leaving it front and rear. Then screwing the two remaining flanges to the deck with sikaflex and normal and then bonding the whole console to the deck on the inside.
Not sure yet which way to go but I know I definitely don't want screws sticking through the hull.

Hightower · 30 April 2008, 21:52

I would hazard a guess that the deck will be at least 19mm thk so 19mm screws won't stick though. I'd use the longer ones inboard and shorter ones around the outside. The other option is to increase the footprint of the console by making an internal wooden ring that fits just inside the console, if this was bonded too it would make for a much better constuction because of the increased surface area to deck.

BruceB · 30 April 2008, 22:04

The console end right at the join between the deck and hull where it looks like the deck is tapered to fit to the angled hull shape. I will need to carefully measure but rough and dirty measurements tonight (it was raining!) look like the screws go through the tapered edge of the deck and will end up outside the hull, it doesn't look much thicker than the thickness of the outer hull at this point which seems to be around 10-12mm of Glassfibre.
I need to measure more carefully to be sure (quite hard to do so and match inside and outside measurements on both sides of tubes) but I am looking at a backup up plan just in case.
The really worst case is to move the console back to where the hull is wider but this would mean sitting very far back in the hull.

Erin · 30 April 2008, 22:21

I would screw it down if you can, but if not, then if it's properly bonded down to the deck with f/glass then it won't be going anywhere. The chances of you peeling a whole layer of glassfibre off the top of the plywood deck in one go are pretty slim. The sheer surface area involved and the rigidity of the console would make it nigh on impossible without some tremendous force being applied.

AndrewH · 30 April 2008, 22:43

Quote:

Originally Posted by Erin

would make it nigh on impossible without some tremendous force being applied.

Something like the force of several tons of water as you stuff the bow at 25 kts (or more) ... perhaps ...

Granted, we all hope for Bruce's sake that this is unlikely but the old line of "hope for the best, plan for the worst" has a lot of merit. IMHO the risk is not of full shear debonding, but more of a peeling off debonding. Given the height of a console, leverage is going to be an issue. Therefore anything to stop any lifting round the edges (like the judicious application of screws and penny washers as suggested by Hightower) has to be a good idea.

I'd just feel happier with belt AND braces

Bigmuz7 · 30 April 2008, 22:52

I asked my dealer about this on my last rig out, but he poo poohd it and suggested just bonding to the deck and screw fixing would be fine. To his credit on my last two rigs this has worked fine. I still feel that a grp flange round the console base would have been better though .. not least of all to stop the dreaded water ingress to the under deck. Next time I will demand it !!

BruceB · 30 April 2008, 22:55

How is it screwed to the deck with no flange?

captnjack · 30 April 2008, 23:00

Consoles breaking loose almost always cause of pretty serious injuries. Is there any way you could mechanically fasten it down on the inside? Might need to install an access port.

BruceB · 30 April 2008, 23:33

I have an existing flange round the console and have good access inside. You can see the flange in the pic. Even if I bonded it in I would leave the flange front and rear for screw fixing.
My query is how do I actually glass it to the deck on the inside, the actual method and materials bearing min mind I know next to nothing about bonding and glassing.....
Hopefully you can see what the issue is. The hull is coming down at an angle and meeting the deck. Putting long screws into the flange is very close to where the hull is going past underneath due to the angles at the join.

bedajim · 01 May 2008, 05:09

Quote:

Originally Posted by BruceB

I have an existing flange round the console and have good access inside. You can see the flange in the pic. Even if I bonded it in I would leave the flange front and rear for screw fixing.
My query is how do I actually glass it to the deck on the inside, the actual method and materials bearing min mind I know next to nothing about bonding and glassing.....
Hopefully you can see what the issue is. The hull is coming down at an angle and meeting the deck. Putting long screws into the flange is very close to where the hull is going past underneath due to the angles at the join.

Prep the area, sikaflex the flange all around +screw it front and back, then glass it all around on the inside

yorfuoj · 04 May 2008, 09:27

For sure, you have a lot of heigth free between deck sides and hull - seing your picture, I would say at least 5cm.

Simply check by drilling a small hole (3mm) through one side where you want to install the console : you will then know exactly how deep you can drill safely.
And if you drill slowly and check the progression, you will know how your deck is made (top GRP thickness, wood thickness, underside GRP ... free space ... hull if your drill is long enough)

But if you just fix with Sikaflex, it will be more than enough, just take care to grind the gelcoat where you want to glue. And add one small screw in each angle while it cures.
Sika bonding is stronger than GRP bonding, and much more than screwing.

If you wanted to keep the possibility of removing the console - who knows ?...- just add a thin steel wire into the bonding, to help cutting it ! Without it, you break.

BruceB · 04 May 2008, 10:26

The console is a lot closer to the hull at the front of the console. The problem is only the first three screws at the front on each side.
After talking to Humber it seems that as long as I sikaflex it in and put all the remaining screws in properly that it will be fine.
I may glass the sides in anyway as a belts and braces job but it seems the worrying is for nothing.........

Endeavour · 04 May 2008, 14:46

If it was me then i would sand the flange and approx 2" up the product. Pur the console in the place that you want it to be. Mark around it inside and out and drill the flange (if it has one) where possible. Move the console away from the area and apply the sika or bonding paste (in our case) and then move the console back in postion and screw it down. Smooth out any excess bonding paste and lt cure. Then glass the inside from the console onto the floor (approx 3" on either) and glass the flange and up the 2" all the way round. Job done.....

BruceB · 04 May 2008, 15:01

Some of these problems are caused by specifying equipment that isn't normally fitted to Destroyer hulls. The console and underfloor trunk being the two main additions.
I should be able to work around the console fitting by screwing down and glassing the inside of the console in. I don't want to glass the outside as you suggest for two reasons-
I want the edge of the flange as a raised part as I am fitting Treadmaster decking and this is the normal place I can make a smooth join and I am not that sure the Glassing will be as neat as yours!
On the inside I don't mind it being rough, nobody bar me will see it!

Endeavour · 04 May 2008, 15:11

Why not taper the flange with a sander. If your edges on the finished glass are not neat, then sand them. Even i have to use a sander some times...

BruceB · 11 May 2008, 23:13

What materials do I need to glass in the console? Fastglas kits are the limit of my knowledge about glassfibre........

mike-stgt · 12 May 2008, 10:32

Hi,
i prefer screwing and bonding.
For security i would drill a 5mm hole in every corner of the console and a 3,5mm to the bottom . Then fix it and tape the console with a overstand of 5mm . Also do to the bottom. Then disassemble again , clean it with acetone , give a line or two to the connection area of sikaflex 291. Srew the console down with 4 -4,8mm x22 screws lightly to the floor . Take some tool like a spoon and make a clean , round flange . Then take the tape away. Don`t take too long screws, because the bottom is about 20mm thick and you will get through all and the moisture will get to the wood from inside.
Dont take nitro -thinner or white spirit for cleaning. It will last an oily surface and the Sikaflex will not bond .

Greetings Mike