Canpa Hatches

[DeLam]

Sorry if it`s been posted before but I`ve not seen anything.
The question is my old Canpa hatches have started to become
"crazed" and I would like to know if and when it becomes
a safety hazard - is it likely to shatter ?
I would like to replace the "Perspex" but the prices quoted would seem to say
I might as well buy new hatches.
The price of the perspex is not all that great so it is obviously labour costs.
Can I do it myself? The question here is how do I remove the old plastic as there appears to be no holding screws. I suspect it`s only held in by sealant.
A good blow with a hammer would probaly do the job ( taking safety measures)
But what sealant would be best and what sort of gap should there be
between the frame and plastic?
Any advice would be welcome .
Thanks in advance

 

[30boat]

I have one of those and recently replaced the acrylic on it.I used Wurth windshield sealant to glue the acrylic to the frame.This sealant comes with a primer that is essential otherwise there will be no adhesion.I aplied the sealant rather thickly and then put the glazing on top of it after priming all the mating surfaces.I then gently pressed on the acrylic to make sure there was full contact and let it to cure for a day.I took the care to mask the surrounding area to make cleaning easier.I then drilled through the acrylic and frame and bolted the whole thing together for good measure.
The hatch has been in service for 6 months now with no leaks.

 

[jimboaw]

I just had 3 hatches re-glazed at considerable expense by a local company. I dont know if they are "Canpa" but they also have no mechanical fixing for the acrylic other than the adhesive. These so called pro's used 3M 5200. It lasted a month.
Did a whole load of research and Sikaflex would seem to be the only product that claims to be suitable.
However, like you, I am thinking that a modification to the hatches would be a good idea for safety's sake.

 

[Chris_Robb]

You should be able to extract the old perspex as it is only stuck in. Silkaflex or any high bonding sealant - i think their are polysulphides and polyeurothenes, to bed replacements. Get hatch covers made to keep prolonged sunlight off the hatches - which is the chief cause of the breakdown - though not in England!

I have just checked my forehatch hinges, and they were almost worn through. The replacement hinges can be got from Spirol and are known as Spirol Split pins, web site WWW.SPIROLDIRECT.COM

 

[chas]

Same hatch, different problem. Have you any idea how to get the latches off? I have a leak round the seal which is in quite good condition. There are two plastic washers twixt latch and hatch and if I can take one off on each latch, I am sure it will seal better. There seems to be a grub screw on each latch with an Allen type hole but neither my metric or imperial allen keys will fit.
Would be grateful for any ideas.

 

[charles_reed]

The crazing is due to UV degradation and it's almost impossible to get rid of.

Your hatches are probably glazed with 9mm, acrylic and whilst the crazing looks thoroughly unsightly you're unlikely to have any immediate risk of implosion.

I just reglazed my 24" square hatch for £140, buying in the UK - if I'd done it locally, in France, it would have been £90, but the UK price included replacement rubber moulding, a new ventilator light and all the sealant.
I think you'll find this about 20% of the cost of replacing your hatches with comparable quality ones (the Canpa hatches were quite well engineered).

Try talking to Patrick Cole of Salford House Services - he tends to be used by the professional restorers.
He lives just outside Sevenoaks and his work phone no is 017324 64635.

He'll even come and do the job for you - but the price will reflect the additional work.

 

[jonjo]

Re: Canpa Hatch - rubber seal

Can anyone point me towards a supplier of replacement rubber seals for this make of hatch.

 

[jcr]

They are not allen screws, they are mill pins and therefore there is probably a lot of corrosion between the aluminium and the steel. If you can get them removed, the handles unscrew. Using a hammer and drive pin is a dodgy business with the hatch in place. A pressure device such as a portable vice squeezing a smaller pin into the hole, with a spacer on the other side to accept the pin being driven out is a better option if you can get access

Best of luck

 

[vyv_cox]

Re: Canpa Hatch - rubber seal

CANPA are no longer in business. Their spares were marketed by Plastimo but there are not many left, a willing chandler may be able to assist in locating what you need.

The perspex is retained in CANPA hatches by small self-tapping screws that screw direct into the plastic, plus sealant. It is not particularly difficult to replace the sheet yourself if you are familiar with the shaping that is necessary to get a good fit.

You have a choice of perspex or polycarbonate replacement sheet. Polycarbonate is far tougher, more expensive and possibly will degrade more in UV. Be very careful to use the correct sealant. Sika make one (only) product suitable for polycarbonate. This is Sika 295 UV. See <A target="_blank" HREF=http://www.sika.com/cmi-marine/cmi-marine-products-index.htm>http://www.sika.com/cmi-marine/cmi-marine-products-index.htm</A> Alternatively, a non-solvent based product, like silicone RTV, will not cause stress-corrosion cracking in polycarbonates.

The question on the leaking of the latches - the handle fastens with an axial self-tapping screw on the inside. Removing this will enable disassembly of the handle. Srealing is provided by a very small section O-ring, quite difficult to obtain replacements from marine sources. The tightness of this O-ring against the counterface is provided by the self-tapper, so leaks down the handle can be stopped by tightening it a little more. There is a limit, of course, so buying new O-rings is a wise precaution.

 

[chas]

All is now clear. Thanks very much.

 

[Chris_Robb]

You mention Mills Pins, are these the same as Spirol Split pins? I need to get some more to replace the hinges that have worn/corroded away on the forehatch. Where can I get these mills pins, as I can only buy the spirols in inductiral quamtity (500!). I had to dril the old ones out, leaving a 7 mm hole. I presume I buy nominal 7 mm pins. and bang them in, or do they need squeesing and then inserting?

 

[charles_reed]

O-rings and latches

I've found, providing you have the correct cross-sectional area a satisfactory replacement can be cut from a section of a larger O-ring - chamfering the join and using a drop of cyano-acrylate to bind them.
The white Nylon washers, often asociated with the through-hatch dog-catches are, in fact spacers and should be fitted on one or the other sides of the acrylic to ensure the latches pull the hatch onto the seal with sufficient, but not to much, force.

 

[jcr]

Re: Canpa Hatch - rubber seal

Try Alexander Comrie & Sons Ltd Millbrook Southampton. Tel 023 8070 2911. I got the impression that it is a stock item, although you may have to buy a long length.

jcr

 

[jcr]

Yes, mills pins are the same as spirol, but I didn't know that spirol claimed to have invented them until I just looked at their web site.

Do NOT squeeze them. The correct size pin can be driven into the correct size hole quite easily, but carefully, with a hammer. If the hole is too small however, it is very easy to burr the end of the pin.

I should think that it would be quite easy to buy small quantities if you can find the right retailer. I would try the many companies that specialise in fasteners. Another source might be your friendly local car repair garage.

 

[jcr]

Sorry I couldn't complete my previous reply to you, I was dragged away by SWMBO. The nylon washers must have been added by a previous owner in an attempt to stop a leak. The designed leakstopper is an O-ring on the handle shafts so, if you manage to get the handles off, it is the O-ring that needs to be replaced. I had a terrible job finding replacements, eventually getting them from a small plumbers merchant who had a selection box. The big plumbers chains are useless, having blister packs of limited sizes only.

 

[chas]

Again, thanks. I will have a go this weekend.