Posts Tagged ‘ Mould ’

Drum Contest

Ok, so I am entering a drum contest. AT http://www.dfdrumtech.com (drumfoundry’s forum)

The shell below is what I am thinking of entering, also I have been making another shell that has blackbutt on the outer plys, this may become the shell not sure yet, what ever looks better with the hoops.

Im planning on keeping my tutorials going with how to laminated veneer together. and Im trying to work out a better pressure system for the molds, will let you know when its all going good.

How to make a Ply shell Mould.

So here are the steps to make a ply shell mould, it is pretty simple and it should only take you two three days to have a working mould come out of it. If you have any issues or questions feel free to leave a comment.

WHAT YOU NEED

Materials

MDF – the thickness is your choice. But generally I would go for 16mm or 18mm, the amount you will need will vary on mould size but I will let you work that one out.
BendyPly – or MDF, something to line inside to make a smooth cylinder.
Hinges
L Brackets
Wax – of the candle variety
Screws
Glue – just wood glue, or PVA would be fine

Tools

Drill – with screw-driver attachment
Router – with straight bit
Jigsaw/table saw/ hand saw – doesn’t really matter what type as long as it cuts.

METHOD

1) Grab a book or blank piece of wood and work to work everything out. You need to figure out the size of the drum you wish to figure out and work back from there. This will get you the size of the circles you need to cut, the height (depth) of the mould (worked out by the thickness of the MDF) Also plan out the process and how you are going to do it, this will make everything run a lot smoother. Remember a drum is not the exact diameter described. So a 14” drum is more like 13.875” remember this when planning out your circle jig.

2) Once you know the size of the drum you wish to build you can the cut up the MDF to the correct size (I plan this before I buy the MDF and get the shop to cut it for me) if you are doing a 14” drum allow for about 2” either side to create the support (making an 18”x18” square.)

3) Now to make the Circle Jig. It is quite simple really. Get a piece of MDF and your router. You need to attach the router to the MDF, each router has different screws in different places so if your router has a removable base plate – remove it and trace it onto the MDF. Once you have drilled the holes, attach the router with a ¼” plunge bit and plunge the hole into the MDF. Next you will need to make the hole for the centre of the circle. To get the location of the hole you will need to draw a line through the centre of the hole you just plunged. To get the length you will need to get half of the diameter of the drum then add the thickness of the bendyply.

4) Mark the centre of the MDF squares and drill a hole. You can screw the circle jig onto the square, or what I do is take the drill piece out of the drill and use that as a centre piece, providing the drill bit is thick enough – too small and it will snap.

5) Make sure it’s clamped and then check the clearance to make sure the router will spin freely without getting caught.

6) Remember safety when using the router, dust mask (as MDF makes fine sawdust) goggles and ear plugs. Use tight fitting gloves if you wish, but loose ones will pose more of a threat then they will keep you safe.

7) On the first piece plunge slightly take the circle jig off and measure the circle. Make any adjustments with the with the jig plunge slightly again, measure and if this is right go ahead and cut the circle out. (as you can see I needed to make a few adjustments)

8) Next cut up the spacers, and lay up the mould with-out glue. Check it’s the right height and make any adjustments. Glue all the pieces together and then to make it a nice cylinder put the bendyply in the middle and the force should move the pieces into place – then clamp. When stacking the MDF only allow for 1-2” in-between. Generally I only stack one piece in-between the circles. So that’s either a 16mm or 18mm gap between the circles.

9) After the glue has cured, get out some sand paper and fix up and bumps etc from the mould. Then glue the bendy ply into place. I generally don’t measure the bendy ply, but if you do it right it shouldn’t need force. I add the gym ball just to make sure it’s going around the to conform to the circle perfectly.

10) Attach two more plates either side of the mould, after they are attached cut the mould in half. Once the mould is in half you can cut any excess off from the mould. With this mould I will leave it on as I will be experimenting with a few things.

11) Wax up the inside (this will help stop the glue from the shell making the shell stick to the mould)

12) Next you will need to attach the Hinges and brackets (this will allow the mould to be opened) the two L brackets will form the lock. When you place the two halves together remember to make up for the thickness cut out so that it still forms a perfect circle.

DONE.

10″ Mould

Currently making a 10″ mould, have all the peices cut now just for a glue up. Hopefully it all goes better than the previous ones. I threw away my first this morning and havnt even finished off the other 14″ I should but im lazy. I might try to finish both tomorrow.

Its going to be able to build 10×10 drums.

Success

OK, so I have got the plys to get press completely flat. What I ended up doing was applying glue to both the Horizontal and vertical leaves of veneer. Then when I clamped the MDF together I put a long 90×35 flat on the top and bottom and clamped to that.  The glue was also applied thinly.

I put a few into the shell mould last night, but that wasn’t a success. The plys were boned nice and tight, but the seams were awful. That is something that I really need to work on.

Mould MKII

SO I started making my new mould today, Its all glued up, clamped etc. The BendyPly isn’t glued down yet. I will do that tomorrow.

The set up is 600x600mm Squares with circles cut out. The spacer between the squares is 16mm MDF, the layout of the mould makes it a little deeper than 8″ meaning it can produce 14×8 snares.

It looks like the quality of the mould is going to be a lot better. The only problem is that its heavy as anything. So tomorrow I will glue the BendyPly in, cut it in half and add the hinges and L-brackets.

The Big Reveal

Today I pulled the shell out of the mould. Everything went OK, could have been better and could have been a lot worse. So there was no gaps in-between any plys which is a good thing. There has been a few issues with the plys moving after the pressure has been applied, I think this is to do with the PVA glue. And the only other issue is the seams, I Need to get the each leaf of veneer measured exact; the seams looked perfect in the mould, but moved out about 2-3mm.

Some things that I have learnt from this shell:

  • PVA glue takes WAY too long to cure – 24hr isn’t enough. The time is too long, so I will switch back to Titebond III.
  • PVA glue is more prone to rippling – this could also be an issue with clamp time, not sure.
  • The shell will stick to the mould – this is pretty common sense, if the shell has glue being squeezed out at the sides, it is going to glue itself to the mould. I think this can be overcome by either coating the shell in a few coats of tung oil or similar (because that stops glue from sticking so well or using wax paper in between the shell and the veneer.
  • I need a new mould – This mould has broken, glue has become unstuck and I don’t think it’s strong enough.

Any suggestions? Feel free to contact me/leave a comment.

Got Some American Walnut.

So Yesterday I went and got some American Walnut to start to make the drums.  17 leaves 300x2400x0.6 to be exact. Plenty

I started off by laminating two leaves of veneer together. All went well, then I did another two and put them in the mould. As I did this, I wanted to create a 7ply drum so that the plys would be (H V) (H V) (H V H) the brackets represent each lamination. So as the drum was in the mould I decided to do three plys at once, to reduce the time that the shell had to sit in the mould, and how many times I had to re-pump the mould.

I don’t know what happened but this lamination turned out awful. I left it for the right amount of time, but it just didn’t work, the glue didn’t bond with the timber. so i threw away that idea. I left the drum in the mould over night and took it out this morning. It turned out pretty bad. It is because I didn’t apply enough internal pressure. I really need to get an air compressor. The seams were pretty bad as well, but discussing it i think i have found ways to make it better. The plys fit real nice and other than some of the wood not bonding it turned out OK. I have started to laminate up a new Drum today. Learning from my mistakes.

I’m still deciding if I want to get a cheap air compressor (like one that you use off your car battery), just to get the extra pressure or go all out and get little bit more expensive but still relatively cheap air compressor (like one that has a tank etc)

%d bloggers like this: