hatch goo

[neil_s]

Evening - and a happy new year to all.
All the see-through plastic on my 30yr old Seal has gone crazy. The big job this winter is to replace it. The windows are fairly straight-forward, but I have a Canpa fore hatch which needs a bit more thinking about. The old plastic was 1/2 inch thick, bedded down into silicon rubber and held in with four (only!) self tappers. The silicon rubber is obviously the primary means of securing the plastic. How should I prepare the frame to receive the new plastic? for instance, do I need to clean off all the old silicon rubber? Will new silicon rubber stick to old? Is a primer necessary? Should I abrade the metal frame? I'd be very interested to hear from anyone who has had a go at this.

Cheers! Neil

 

[VicS]

Rather than use a silicone sealant again why not consider Sikaflex®-295 UV, a fast-curing, one-component, flexible, high-performance polyurethane-based adhesive for bonding and sealing of windows and portholes. Sikaflex®-295 UV is suitable for all types of organic (PC, PMMA) window panes. Its available in black or white.

http://www.sikaindustry.com/ipd-marine.htm

Being a better adhesive than silicone it may be a better bet with the small number of screws you have.

You will have to remove all the old silicone but if necessary maybe a silicone remover from a DIY store will help.

Don't abrade the frame if it is anodised but for best results use the Sika primer.

The down side of using a Sikaflex may be that next time round it might be very difficult to get the old glazing out of the frame

 

[mikejames]

Yep - Sikaflex is a brilliant alternative, it sticks amazingly - I have splintered teak in the past trying to unstick it from sikaflex.
I use silicone sealant if I think I am going to need to remove or replace within a couple of years.

 

[homa]

refurbishing my hatches

I replaced the acrylic in both my CANPA hatches 3 years ago.

I first looked at having it done profesionally and was agast at the cost.
In the end I did it myself. Very straight forward and not difficult.
Firstly I took the hatches completely off the boat and took them home to a warm garage. I bolted the hatches to rough wooden frames to prevent any distorsion - not sure if this was really necessary, but it did protect the frames from any permanent distorsion due to the heavy handling whilst removing the old acrylic. I then removed the old crazed acrylic with a hammer. The larger hatch had 12mm acrylic and the smaller had 10mm thick acrylic.
I cleaned up the aluminium frames with a wide blade screw driver and finished off with wire wool - making sure not to leave any wire residue as it will rust later.
I then took the now clean empty frames to an acrylic supplier and had them cut the material to fit. They recommended marine grade silicone sealant for this (the old acrylic was fitted with silicone).
And refitted the frames to the boat with sikaflex.

I was quoted over £500 by a specialist firm to do the job, cost me just under £100 in the end.

Oh nearly forgot...l also renewed the neoprene seals on both hatches - very easy and cheap from on-line suppliers (a couple of £'s per seal)

 

[neil_s]

Re: refurbishing my hatches

Thanks for the tips, Homa. I have already got the acrylic out of the frame - it came out easily and in one piece, so I have a pattern for the supplier. I have not taken the hatch frame off the boat. I was interested to see that the acrylic was 1/2 inch thick, yet the crazing was limited to the top 1/16 inch, so the strength was not seriously compromised. Good tip about replacing the seal.

Cheers! Neil

 

[neil_s]

Sikaflex it is - I don't intend to be around to do it again!

Cheers! Neil