Thanks for the reminder Iv'e just reserved a tin of textured paint from Halfords and Ref the colour scheme, I am thinking of joining the York model boat club and at an open day a few weeks ago I was talking to a club rep who actually served on the two RAF boats I will try and contact him and ask the question
Now the Chine rubbing strakes are fitted, dry and filled and I have attended to the minor lumps and bumps the next job is to give another coat of resin, taking the issues of the first application into account I intend to apply a thin coat, this has the effect of filling in the pattern of the glass cloth. Another two days have passed and it’s time to do some rubbing down. I have found that the surface is very hard, more so than I recall some of the other fibre glass projects I have done but these have been using Polyester resin. It’s a first for epoxy, so is epoxy a better choice than Polyester? According to my mini research – Epoxy is more versatile Epoxy has fewer fumes Epoxy is stronger Epoxy shrinks less Conclusion Epoxy is the better choice for repairing/covering either wooden hulls or repairing fiberglass boats. It has excellent adhesive qualities, wets out fiberglass fabrics and it is tough. It has great thin film cure characteristics, cures in cool temperatures. After the first coat I wasn’t 100 % happy with the finish but I just thought that some dust had landed on the surface before the resin had dried, (this was proved not to be dust but because of the matting pattern still been visible it disguised the real problem) however this was easily sanded out with wet & dry. Now the hull and deck were looking really smooth with very little sign of the matting pattern it was time to give a final coat. I had decided to coat both the deck and the hull in one go so I mixed enough resin to do the lot. Starting with the deck I started to apply the resin but to may horror it started to pin prick all over the deck surface, panic, panic what was causing this? So was it the brush which I had previously washed out with cellulose thinners after applying the last batch of resin. I decided to remove the resin and use a new brush (I had 90 mins cure time to do this) so cleaning of with paper towel and finally with a wipe with thinners I started to apply resin again – but it happened again as I sat in despair I looked into the pot of resin wondering where to go next when I saw a film on the top of the remaining resin It was then I noticed a ridge in the cups side. It was the wax coating that had melted into the resin and subsequently appeared as pin pricks in the newly applied surface. At this realisation I removed all the resin again and took a breather hoping I had found the problem. Another day and a light rub down of the deck to make sure the surface is ready to receive its final coat. Resin weighed (in a glass container this time) and well mixed I started to apply again and fortunately it was OK and all surfaces were coated.
As the hull glass matting is really dry and has had some minor filling done it’s time to fit the chine rubbing strakes. which have been in the jig now for some days and consisted of a two dimensional curvature jig. In order to make sure the strakes were equally balanced on each side I made a cardboard template that followed the Chine stringers line and rested on the Gunwhale rubbing strakes, having drawn a line on the port side I flipped the template over and drew a line on the starboard side giving a perfectly equal curve on each side So now to prepare them for fitting. The jig had made a curve that was a really good fit without much spring. I decided to use some very small brass pins (0.5dia x 10mm long) to hold them whilst the epoxy sets. I pre drilled the whole length of the strake and lightly inserted pins along its length, then applied the epoxy and started to fix from the bow and followed the pencil line back to the stern. This was repeated on the other side, when set there was some minor filling to be done/filling pin holes.
Since I had been finishing the Gunwhale rubbing strakes and had the boat right side up and I was going on holiday for a few days I decide to glass the deck this would give the deck time to set. So some fine filling and then cut the matting to shape. Again I put a light coat of resin onto the deck then allowed the matting to sink into the resin, a minimal amount of brushing is required and then its left to harden overnight. The resin is now sufficiently hardened after two days so before I go away I can apply another light coat of resin which fills the matting pattern very easily - a week away now will allow the resin to harden fully.
Annealing brass agreed you need to anneal brass if you are bending it, this is easily done by first cleaning it and then heating to very dull plumb color (600 degrees) and then quickly quench in water, don't forget that brass work hardens so if you are making complicated shapes its a good idea to anneal part way through the bending or repeated hammering process.
Gunwhale rubbing strakes As these pieces will be under stress they need to be steamed into shape prior to fitting so out with the wallpaper stripper and modified tube (1/4 BSP fitting in the bottom of an old piece of IKEA cloths rail).For the gunwhale strakes I used the same former as I used for the stringers so 20 mins in the steamer then into the jig for 2 days drying. The chine rubbing strakes will need a different jig but this time a left and right hand version as not only do they bend round but also up at the bow. I was however disappointed with the quality of the 3/16 square obeche as the grain was nearly at 45 degrees to its length – it snapped before I started to bend it, just pushing it into the jig I bought some better pieces from the local model shop. I temporally fitted the gunwhale rubbing strake slightly proud of the deck level in order to drill all the pin holes then remove and mix up some epoxy, coat the length and hook into the brass bow and start tapping in the pins along the length of the boat, repeat on the port side. Chine rubbing strakes are still in the jig!
Before I do the final coats of epoxy the rubbing stakes need to be fitted but then Robbob pointed out the vulnerability of the bow particularly when transporting through doorways. I decided to take that advice and make a brass bow bumper, this will not be visible when finished but will stop any structural damage if the bow is hit, it was screwed and epoxied in position. The design also incorporates a location for the rubbing strakes holding them in position when fitting. Thanks Robbob
I suggest you thread the end of the 600mm bar and don't cut it to length first, so hopefully not, but if it does go wrong you can just cut the end off and start again. I always do the most complicated job on a piece of work so if it does go wrong you haven't wasted any time on other processes.
I purchased as recommended by Robbob the fibreglass package which consisted of 750g of epoxy resin and 250g of hardener, I also went for the 90min cure as this is the first time I have ever done a boat hull, I’ve done plenty of stranded fibre cowlings/air intakes etc. where you lay a gel coat first then stranded matting which is so different to laying a fine matt on its own. I also ordered some mixing sticks and throw away brushes. First I cut the matting to the slightly oversize for one of the side skins, then loosely taped the matt to the bottom skin and checked the coverage - and checked again then fold over to the opposite side, this then leaves the surface clear to apply the resin. Mixing the resin should be done accurately, so borrow the kitchen scales and here we go. I wasn’t sure how much to mix for a side skin but 25g of resin and 7.5g of hardener looks about right. So mix well and then brush onto the side skin, then I gently lifted over the matting and laid it on the skin and gently brushed the matting down, the matting is almost sucked onto the resin so minimal brushing is required to ensure a smooth surface A previous blog said that “Less is More” how true this is, the temptation to spread the remainder of the resin on to the already adhered matt is something to be avoided, however learn by my mistake as I did just that (only in a small area on one skin) leaving rather a lot of sanding later after the resin had fully cured as it leaves a rather lumpy surface. So onward and upwards the following three surfaces were relatively easy with only minor difficulty keeping the matting in close to the 90 degree angle between the keel and skin and I had to keep going back to it pressing it in with a steel rule until the resin started to go off but minimal resin left a surface that was flat and the weave of the glass matt can be clearly seen and felt but minimal sanding is required if at all. Then a further 2 coats of resin with sanding in between will leave a smooth surface ready for final preparation of painting. The final picture is of the roof that in a previous page I said to add strength the roof would need a coat of glass to reinforce the unsupported edges – To be continued
A really well attended show over 3 days there were lots of stalls selling mostly tooling type products but a good few boat related parts as well. There were lots of steam related stalls serving the model traction engine and steam train community, however the show of boat clubs was very disappointing (only 3) anybody know why? Still I had a great day and spent loads of money.
Go for it, but be very careful when sizing the shaft and bearing fit, use very fine 1000 wet and dry until a slight interference/push fit is achieved. and for the M5 thread make sure you open the die to its max on first cut using lots of quality cutting oil and then finally finish to size gradually closing the die to it neutral size, It also helps if the die is new as Silver Steel is quite hard in its natural state. (sorry if this was teaching Granny to suck eggs)
Radio control roof ? not sure about that but yes the cabin is already detailed see earlier in the blog and final pictures will follow when all the metalwork is completed. Roof only opens to be able to see internal detail
Now that the internal detail of the cabin has been finalised and fixing points made for each of the panels and floor pieces (all parts of the cabin detail are to be removable) I can now finally fit the cabin roof skins. Since the leading edge has an overhang which because of the lifting design hasn’t the same framework support I have decided to reinforce the joint with stainless steel pins.to ensure a perfect fit, I made a tiny jig out of brass angle that ensured all the holes in each piece lined up. I then placed pieces of silicon sheet on the parts I really didn’t want the skins to stick to the cabin framework. Fist all the pieces were position and pinned to ensure a good fit, they were then removed adhesive applied and the skins finally placed and pinned, most of the pins will be removed when it’s dry. The centre panel has an opening for the hatch so this was put in prior to fixing. After a day’s drying it’s time to see if the whole thing works as envisaged, thankfully it does. The roof will now have to be dismantled so further work can be carried out it, will also get a covering of glass matting to add overall strength.
Andy, your best going for 5mm silver steel as it will be more likely to be a better size and will run true. Not sure what the total length is of the shaft but your not limited to the normal 13" lengths as its available in 1 mtr lengths from a good steel stockist.
Having remade all the front cabin window frames I then decided to fit the acrylics into the opening (nice tight fit) all done! Or maybe not, someone then said how about “opening windows” it’s been done before. So would opening windows be a problem with water ingress? And would putting foam seals solve this problem? I’m not convinced. Having given the problem some days thought, how about going with the windows as planned which are now 1.5mm thick and inset into the surround. Then fitting an over window frame 1.0mm ply/plasticard with another thinner (1.0mm) acrylic window and hinging this above each window. This would solve the issue of water ingress and also give the appearance of opening front windows. Looking at how one other person approached this, it looks like the hinge was a brass tube across the majority of the window top and then a shorter piece the same dia tube at each end with an internal wire for rotation these short pieces are then fitted to the body of the inner window frame. These additional window frames can be added at a later stage and this doesn’t hinder the final finishing of the roof skins. So final fitting and adjustment and then pin and clamp in position the forward roof skins. When these are dry the window frames can be finally trimmed and then pinned into position and checked for fit then removed and then to each one apply the aliphatic glue and fit –pin and clamp in position