Infusion Plan

Yes you told me 2 inches but I figured since I was infusing inward and the length was double the width, that I would need more break, but apparantly not.

 

Hi Jorge, so I see you have a lot of fun with vacuum infusion. My compliments! and keep up the good work

 

Thank you Your project and kit along with all the advice here was invaluable. Shooting the last of the components this week!!

 

Quick Question: How do I attach deck to stringers???

I plan on glassing along the outside flange to keep it attached to hull and at the points where the stringers project above the deck so it's not going anywhere but to provide a support along the middle, I thought I would glass it at first but that is going to be hard to do ,upside down, in a tiny little space, on my back.

Now I am thinking some kind of adhesive like 5200 or just a sealant that gives a bit of flexible support and that I can dispense with a caulk gun?? I have a feeling if I use bog, that stuff will just crack over time unless I glass it too.

The deck is not going anywhere, I just don't want bounce or slamming against stringers if somebody happens to jump down from a dock or falls etc ... Any advice appreciated!!

Getting Close!

 

Jorge, how we do hard to reach places or voids, is to first make some "bonding angle" which is simply a 90deg angle section of solid glass. Make it up from strips or glass off cuts or pre made glass tapes. Lay them up on a heavy steel RHS section as a kinda mold or tooling surface -so you get the small radius around the edge with no voids. Use peel ply both sides so when they're cured peel it off and glue them on.

Anyways, make these up and glue them to the top edges of your stringers. Once they're glued on with thickened epoxy, mix up more thickened epoxy and apply it to the tops of the bonding angles and lay your deck down onto it, weight it down and give it plenty of tapping to settle it down. Job done.



This following pic show the bonding angles glued in place, ready to accept the lid;



To make the angles, i used 2 peices of glass tape, generally somewhere around the 750gsm - 600gsm weight.

When you glue them on, a good method is to use a tile glue adhesive trowel, the ones with notches in the blade. This allows you to get some thickness to the glue mix to take up any unevenness/out of plane level to the mating surfaces. Otherwise you will use a ton of glue to get the job done without risking parts of the mating surfaces having no contact with the thickened epoxy.

 

Thanks Groper!! I understand now ...
Do you also tape the angle to the stringer?
What do you think about flexible adhesives instead of epoxy bog.
Will the epoxy bog crack since it has no flex?

 

Hi Jorge,
Its becoming common practice not to glass tape joints. You can use a structural urethane like sikaflex or an acrylic like Plexus. Saves a lot of time and effort! In various tests we have done the fibreglass always tears apart not the joint. So its easy just trowel or gun the plexus say into place or on stiffener/part edge. Place the stiffener on the bead and settle into position. Then cove the squash out, perhaps add a little more if needed to make a 12 or 20mm cove whatever you whould usually do and leave it at that. (we use tongue depressors) The survey people are accepting this practice these days as well so must be OK. Cheers Peter S

 

Peter, are you saying that the fibreglass tape is not required? So just cove the adhesive mixture and leave it at that? If so, would i be correct to assume that this only applies to non structural joints, like stiffener to panel joints as you gave example of? What other areas are acceptable to do this and what joints are definately not? What about using high density thickened epoxy mixtures, or does it have to be a flexible adhesive?

I just spent all day taping my boat together and now i have to fair the tape joins out on otherwise perfectly fair panels, would save so much work not to have to use the tape...

 

Jorge, the angle IS the tape, it goes where you would normally tape if you could access it to do so... so no, you just glue the angle to the stringer first and let it cure making sure all of them are "in plane" , then glue the deck to the angles and stringer tops in 1 shot.

 

Correct, the tape is not required even for structural joints. A bit of give is good but even survey will now accept joints that are not taped. Have to provide calculation or test evidence but they generally fly through this. We have just tested a connection that has to hold 1T and it failed at 7T. The adhesive was Plexus MA425 from memory. The laminate tore apart each side leaving the plexus in the middle. Cheers Peter S

 

Bloody hell... wish i knew this about 12 months ago... So let me get this straight, let say i have a hull panel to bulkhead joint. Both hull and bulkhead are foam cored sandwich panels. I just calk a heap of methacrylate adhesive into the bond area, place the bulkhead, cove off the excess, and thats it?

 

Prove it !! pictures and photos and official evidance !!!

sorry not taking you word for what you just wrote until I see that in official survey report ,writing, printed and signed with the seal stamp of approval I will stay with what I been bought up with and never had any problems with over the last 30 years . less is not durable. and out on the oceans of the world Durability WINS hand down every time in my book !
last thing you need to worry about is will the deck stay there or will it come apart like a tin of sardines !! Hull and deck join peel end to end a 30 mm wide stuck joint against a well glassed 200 mm wide deck join of glass and resin don't think so ??

 

Yes thats it. Hard to get head around but the survey guys have finally realised that the shear in this area is quite low and the usual rules create a joint that is dimensioned to take the full flexure load in the centre of the panel not the edge shear. LR's rules of 2009 (an old copy) classification of SS craft vol 6, part 8 section 1.18.10 states "alternative bonding arrangements incorporating epoxy fillets... ... it is the responsibility of the builder to demonstrate ... equivalence to the Rule requirements." Calculations and tests show that epoxy, urethane or PMMA adhesives all can support the required load at the connection with no need for a cover laminate. I personally prefer PMMA after testing each one for a particular application. Mainly because the prepartion requirement with PMMA (like plexus and scigrip) is minimal. Peter

 

sorry you can write what you want!

sorry you can write what you want !!pages of it and quote figures till the sun goes down and rises again I would never use just those kinds of adhesive without a secondary back up !!no way and as for mounting bulkheads you are a fool for believing its that easy !! So when you drifting about clinging to what's left of your broken boat remember you were told !!!
I have uses plexus many times but like I said I would never hang my life or anyone else's life on a skinny deck join or any other join against a wider glass/ resin join !!!
Building inflatable boats there adhesives will tear the glass surface off to bare glass or gel coated glass what ever but there joins are wide not narrow . once you tear the glass it become a peel ability issue ! yes the adhesive is still holding onto the glass but its the glass layer that's giving way ! Get the message !!!:idea:

 

Hi Tunnels, no problem staying with what you know. Cheers Peter S