Overland caravan build

[miketomcat]

Unfortunately I can't make it but I'm sure ju or someone else on the committee could be persuaded/can stick it in the club trailer for me. Thank you very much.

Mike

[FridgeFreezer]

54 minutes ago, miketomcat said:

Unfortunately I can't make it but I'm sure ju or someone else on the committee could be persuaded/can stick it in the club trailer for me. Thank you very much.

I'm sure I can bring it back for a very reasonable fee

[Nonimouse]

Whats the PCD?  I might have  couple of rims

[miketomcat]

Just now, Nonimouse said:

Whats the PCD?  I might have  couple of rims

5x6.5" (land rover) in 13" rims I have 4 12" rims three have good tyres that I would happily swap.

Mike

[Nonimouse]

50 minutes ago, miketomcat said:

5x6.5" (land rover) in 13" rims I have 4 12" rims three have good tyres that I would happily swap.

Mike

I'll look tomorrow

[landroversforever]

13" LR pattern means you're after ifor wheels? without tyres I don't think they're expensive new. 

[miketomcat]

10 minutes ago, landroversforever said:

13" LR pattern means you're after ifor wheels? without tyres I don't think they're expensive new. 

Correct, but they are if you don't have any spare cash.

Mike

[miketomcat]

Managed to get in the workshop this afternoon so I've actually made some progress. I've started making the mould for the rear lower extension panel. This needs recesses for number plate and lights.

Number plate recess.

Strip glued up to make the light recesses.

Ironically I need the wheel arches first but I will need to re-use the MDF for each mould so I need to make the biggest moulds first.

Mike

[landroversforever]

Is it just normal MDF or is that some kind of melamine faced stuff? Appreciate it's probably not that easy, but a bit of a step by step for the fibreglassing as you go would be cool to see.

[miketomcat]

It's Melamine faced MDF we use it for plug and temporary mould making. It's very flat and waxes up nicely so releases well. Laminating is relatively easy, doing it without wearing it is the hard part.

Mike

[Wytze]

59 minutes ago, miketomcat said:

It's Melamine faced MDF we use it for plug and temporary mould making. It's very flat and waxes up nicely so releases well. Laminating is relatively easy, doing it without wearing it is the hard part.

Mike

I allway's see it like voodoo what you fiberglass guy's do...   Your kind make it look so easy..   that us mere mortals try it , and struggle 😁

[miketomcat]

Dry day so did some work on the trailer. Wheel nuts off copper slipped and back on (without breaking the new power bar ) Free'd off the brake adjuster's unfortunately one snapped off, I'll have to drill that out later. Welded up the two chassis cracks then while I had the angle grinder out I may of slipped and cut the front extension off.

Also replaced the dodgy jockey wheel.

Mike

[miketomcat]

All the plants are in the mould now plus the first two coats of wax.

The silver is foil tape I've used it to cover the exposed MDF, you can also use sanding sealer/knotting (two coats min) or durabuild/2k high build. As the whole thing is going to be painted I'm not to worried about finish, there'll be plenty of filler later anyway. Next is plasticine radius on all the internal corners followed by four more coats of wax.

Mike

[markyboy]

45 minutes ago, miketomcat said:

All the plants are in the mould now plus the first two coats of wax.

The silver is foil tape I've used it to cover the exposed MDF, you can also use sanding sealer/knotting (two coats min) or durabuild/2k high build. As the whole thing is going to be painted I'm not to worried about finish, there'll be plenty of filler later anyway. Next is plasticine radius on all the internal corners followed by four more coats of wax.

Mike

Very interesting to witness this being done by a pro'.

[miketomcat]

Plasticine around the internal corners.

This gives nice rounded corners and makes it a lot easier to get the mat to sit in the corners later. More wax six coats in all.

I'm using white get because it's the cheapest and the whole thing will be painted later. You can get almost any colour you want including metallics. 1kg of gel covers roughly 1m² so I mixed up 2kg of gel with catalyst @ 2%. If it was colder I'd up it to 3% if hotter drop to 1%. Just a note here catalyst is nasty stuff, gloves and glasses are highly recommended (catalyst in your eye burns and will likely blind you). The mixed gel is then brushed on (larger areas can be rolled on with a mohair roller but you still need to brush it out), the trick is to get it on quickly then go over the whole lot brushing it out evenly. You only have about 20min working time (less if warmer, it can be as low as 8 minutes) once on it'll take roughly 1 hour to cure but it can take longer. The test to see if it's cured is known as the squeak test, once touch dry you gently run your finger over the surface if it squeaks it's ready to go. 

First coat of gel on. This must be covered within 24hrs, either with another gel (you normally do 2 gels) or with your first lays.

Mike

[Wytze]

25 minutes ago, miketomcat said:

Plasticine around the internal corners.

This gives nice rounded corners and makes it a lot easier to get the mat to sit in the corners later. More wax six coats in all.

I'm using white get because it's the cheapest and the whole thing will be painted later. You can get almost any colour you want including metallics. 1kg of gel covers roughly 1m² so I mixed up 2kg of gel with catalyst @ 2%. If it was colder I'd up it to 3% if hotter drop to 1%. Just a note here catalyst is nasty stuff, gloves and glasses are highly recommended (catalyst in your eye burns and will likely blind you). The mixed gel is then brushed on (larger areas can be rolled on with a mohair roller but you still need to brush it out), the trick is to get it on quickly then go over the whole lot brushing it out evenly. You only have about 20min working time (less if warmer, it can be as low as 8 minutes) once on it'll take roughly 1 hour to cure but it can take longer. The test to see if it's cured is known as the squeak test, once touch dry you gently run your finger over the surface if it squeaks it's ready to go. 

First coat of gel on. This must be covered within 24hrs, either with another gel (you normally do 2 gels) or with your first lays.

Mike

Loving this..   Well explained , you would make a good teacher

[Ed Poore]

He's had lots of practice with two daughters 😂

[miketomcat]

44 minutes ago, Wytze said:

Loving this..   Well explained , you would make a good teacher

Actually I'm a rubbish teacher, Apparently I'm to condescending then I get impatient and just do it myself. I don't get given apprentice's at work.

Mike

[miketomcat]

Squeak test.

 

Ready for next coat.

Mike

[Wytze]

2 hours ago, miketomcat said:

Actually I'm a rubbish teacher, Apparently I'm to condescending then I get impatient and just do it myself. I don't get given apprentice's at work.

Mike

Soft and gentle is not the way to learn anything😁😁

[miketomcat]

Normally you would put a second gel on at this point, especially if your not planning on painting and are just having a gel finish.

Now I've been doing this a long time and I'm going to be painting it at some point, so one gel it is. Next up you need to cut your mat roughly to shape, think dress making. You need to allow for some overlap but not to much. There is all sorts of mat/cloth I normally use 450g chop strand mat (CSM) not to thick that it's difficult to work but gives enough thickness to make a 2-3mm panel at 3 layers. I could use woven mat generally lighter and stronger but more difficult to use on complex shapes (this isn't particularly complex). On this occasion I'm using 600g CSM it's quick to lay up, gives good thickness (it'll be 3 layers so 4-5mm thick). 

Next you need to get so tools ready, I use a 4" fluffy roller, a paddle roller and a bolt roller. Have a box of latex gloves to hand along with a pot of acetone. CSM takes 2.5 times it's weight in resin so 1m² of 600g CSM will need 1.5kg of resin (woven cloth is 1:1 hence you need more layers to achieve the same thickness thus stronger). Mix up @ 2% again, wet out the area, if doing a large area split it into chunks (I've done this in two hits roughly 1m²).

Now lay your first layer over the wetted area and wet that out.

Once wetted out thoroughly you consolidate the area to get all the air bubbles out and draw the resin up through the mat. Once your happy you've push the mat tight into the corners and got the air out I give a quick roll over the lot with the fluffy to tidy the surface. This then gets left to cure.

Mike

[Ed Poore]

If its not bloody obvious Mike is damn good at this. I vaguely recall a message from him a few years back.

I'd asked him to make me some dodgy / bad fibreglass and carbon fibre samples (E.g. With dirt, air bubbles etc in it) for a sensing project I was working on for a customer. The message was along the lines that he ****ed up and messed up by not messing up... Basically even though he was specifically asked to do a bad job he failed and had to redo it again to try and mess it up. 

[miketomcat]

Once cured and cooled (probably best left over night) you can de-nib the spikey bits external corners are the worst, you may need to hoover the dust out. After the first layer is on or all other for that matter you have 28 days to complete your lay up, assuming it doesn't get contaminated (if you put your next layer on at 28 days the clock starts again).

Now your ready for the next layers as I'm only doing 3 layers and I know what I'm doing I did all three layers at once. If your a novice I'd do one let it cure then two more at the same time. Maximum of three layers at a time.

As before wet out, add a layer of mat, wet that out. Fluffy down any lumps as you go then add the second layer, wet out and fluffy down. If the mat is bridging and area carefully wet it out and let it soak for a minute then you should be able to stretch it into place, just remember when doing this you are thining the lay up so it may be better to cut or tear it and add a piece.

Again consolidate the area.

And fluffy to finish.

Mike

 

[miketomcat]

I forgot to add earlier once you've finished you need to clean your tools in acetone, you can squeeze out the fluffy and rinse it out but I recommend taking it off the handle and leaving it along with the other tools in the acetone (acetone evaporates so a lid will be needed). It's often easier to admit defeat and just bin the fluffy each time just remember it can get hot as it cures. Obviously this time your not going to be mixing all the resin at once so do it in small batches you can just add fresh resins to the pot and catalysise, but it's better to use a fresh pot until you get the hang of it. Scrape the worst of the old resin into the previous pot before moving it to the new pot (no need to clean it out but remember to do the same with the consolidator) it's worth reducing the catalyst as the previous mix will kick off the next. The same goes on the job especially on overlaps.

When overlapping onto the previous part you need to roll and consolidate the whole of the overlap before the rest of the panel because the previous layers will be curing this gives off heat which accelerates the bit you currently doing.

Mike

[steve b]

This is a masterclass on the subject Mike, you make it look easy. 

This section could be copied and added to the tech Archive as a "How To Mould and Make Fibreglass Parts"

Thanks for the posts Mike.

 

Steve