Finishing a speargun

[Dan Man]

Hi guys,

I'm just wondering what everyone uses to finish their guns and what process. I am after a high sheen finish thats durable in UV.

First I just used marine varnish, while it is good I don't think it is thaat durable. Maybe I just had a bad experience with it because I put too many coats on too fast and it never fully cured.

I then tried some interior gloss stuff but it produced a nice finish I don't think it would last in the UV and sea.

I have now been using west systems 207 (3:1) as it is the UV inhibited stuff. While this is very durable I can't seem to get a mirror like finish, it is always a little 'wavy' sort of. Even when religously sanded to 800 grit:head Then I read you need to put another UV inhibitor on top of the west systems (even though it is the UV stabilised one!) so I went out and got some marine spar varnish.

Now this spar varnish was RUBBISH! It took AGES to fully cure even when thinned and wasn't durable at all, I could scratch it all off with my finger nails.

From what I undertsand about epoxy is that its hard to get a mirror finished because its so thick. So what I am thinking is of using west systems for 3 coats (to get the durability)...then sand to say 1200 grit (starting at 400, 600, 800, 1000, 1200) and then putting a coat of marine varnish (I think if I get a good brand it will be durable) so its all smooth and the thinned marine varnish will give a better top coat.

Some things I should mention...after sanding to 800 grit I vacuum off all the saw dust out of the poors and wipe over with methylated spirits (alcohol) and then let that evaporate and start coating. I am also using sponge brushes, could this be the problem of my non-mirror finishes? I think a brush would be better for the last coat.

Any thoughts or suggestions for me?

:friday

 

[Decca]

Dan Man,

Sounds like you have tackled this from all angles. It was interesting to read what you are trying. As a matter of interest, how long do you allow for the paint to dry between coats. I wonder about using methylated spirits as it can leave a film. I seem to remember this when using it to clean windows. I used a rag with turps. Maybe it would be better to just use a damp cloth and wait for the gun to dry.

This is probably like telling you to suck eggs, but for the benefit of those who are tackling this for the first time, I've been using a marine varnish and notice that you require about 24 hours between coats and longer in colder weather. I coat one side, allow it to dry overnight then turn it over and coat the other side. After a further twelve hours it is back to the origin side. It is a time consuming job. It is recommended you apply four coats.

 

[Pastor]

I have the same problem with marine varnish, it just doesnt seem to fully harden. Even 4 or 5 weeks after the last coat it is still a bit soft. I used International Original Yacht varnish (new stock). After one dive it looked like this

and to compare it with a similar unused gun

Both guns got 3 coats of west epoxy and 3 coats of the varnish. Im not overly convinced of the need for the varnish top coat anymore. Well at least for me, my guns dont spend any long periods of time in the sun, I store them in the dark and the only sun they get is the 5 minute walk from the car to the sea rofl and then they are submerged My freind refinished the fancy wooden dor cappings of my nextdoor neighbours convertible sports cars 4 years ago with epoxy. That car is exposed to bright sunlight all the time and they still look like new. To get a mirror finish on epoxy sand down to 1200 grit and then buff with car paint cutting compound (T-cut in the UK) until the look is right

 

[foxfish]

Hi Dan you have obviously experienced the woes of using epoxy! There are lower viscosity epoxy's available or you can thin with acetone to obtain a better finish. I find epoxy is a fantastic product when used as a glue or as a thinned base coat but not very good for top coats.
There are various options available when over coating an epoxy base coat, if you really want a hard shinny surface & you dont own a compressor, take your gun to a spray shop & get it spayed with two pack or cellulose.
If you want DIY, two pack polyurethane marine varnish is a good product to work with. Like most things in life you get what you pay for & two pack is expensive with a short shelf life to boot. However two pack polyurethane goes very hard in a set time & can be polished smooth & shinny.
Maybe the easiest options would be an acrylic aerosol clear lacquer, available from car accessory shops.

 

[Orangekiwi]

hmm, I can't remember where on this forum but I have seen a thread about this. The guy highly recommended using a scraper and NOT sanding it. This way you get a mirror like piano smooth shiny finish. I am sure it was a thread on a homemade speargun. Had a look around this is the thread with some useful advise from oneolddude ???
I am trying to copy the link but it won;t let me ????
under homemade spearguns thread is called customs spearguns pictures
it is a long thread !

 

[portinfer]

I went for three coats West System (slow cure) epoxy scrapped with cabinet scraper between coats (sand paper clogs and scrapping is alot faster in my opinion and probably a better finish). Then I think I used 3 coats of spar varnish - Original Yacht varnish - can't remember the make but you definitely need to leave it a week between coats - other variables seemed to be the relative air humidy and air temp ... cured better in drier weather... I am a novice at this stuff but it seemed to work out ok - guess I was lucky.

I hung the gun up from a light fitting in a spare room and used a small paint brush for epoxy and varnish - very thin coats of epoxy and I thought I was scrapping most of it off - this may have been the case but I got a very uniform coat.

Hung one way up then scrapped when dry (I shut the door for a few days - so minimal dust etc - window open for air etc) - hung the other way and another coat etc.

Obviously this takes a while... I was in no rush so it suited me fine. The gun is holding up quite well - but I have a few 'extra' holes from lead balancing efforts ! THese will get filled in at some point... more of an experimental first gun - learn by the mistakes...

Edward

 

[Dan Man]

Do you mean scraping as in when you strip back paint off a bit of old furniture? Using a blade like scraper? So you just run it up the stock to take off a bit of west systems? I'll give it a go on a test piece of wood and see how it turns out...I gotta stop trying my new finish ideas on actual guns rather than scrap bits of wood:head

 

[portinfer]

Cabinet scrapers : http://www.axminster.co.uk/recno/4/product-Axminster-Hard-Edge-Cabinet-Scrapers-20437.htm

You burnish an edge and make a very small hook of metal - well if you burnish at 90 degrees you should get an edge... plenty on the web about scraping...

Ed

 

[foxfish]

Scraping epoxy works well especially on flat surfaceses but as Ed pointed out it is easy to remove to much of the epoxy, so be careful. You can also use wet & dry production paper, use wet & go down the grades. Use the paper on a sanding block, put a little soap in the water, start with 280 grit & work down to 600. You can flat the top coat of varnish down to 1200 & polish with T cut for a mirror finish.