New Caravan - Construction Methods

Submitted: Friday, Feb 10, 2012 at 21:44
ThreadID: 91794 Views:13094 Replies:8 FollowUps:13
This Thread has been Archived
We are in the market for a new off road full caravan. Before looking at different manufacturers I firstly want to decide whether we will go for the tried and tested steel or timber frame with aluminium or fibreglass sheeting vs the newer composite fibreglass walls (sometimes called structural fibreglass foam sandwich). The latter is claimed to provide better insulation but more importantly lighter weight as no framing is required. Its claimed to be exceptionally strong and has been used in building yachts for a long time. Does anyone have an opinion/experience with vans made with composite fibreglass walls (no framing needed)? Thanks for any feedback.
Back Expand Un-Read 0 Moderator

Reply By: Peter_n_Margaret - Saturday, Feb 11, 2012 at 07:02

Saturday, Feb 11, 2012 at 07:02
Most serious off road motorhomes are built from fibreglass sandwich panel.
When I built our OKA motorhome I used fibre glass sandwich panel on a lightweight steel frame. Having that frame was a mistake.



Cheers,
Peter
OKA196 Motorhome
AnswerID: 477469

Follow Up By: Member - Wamuranman - Saturday, Feb 11, 2012 at 07:29

Saturday, Feb 11, 2012 at 07:29
Thanks good to know Peter.
I like the idea of the sandwich panel - but wonder why most manufacturers still prefer to use the old framing method. My estimate is that using sandwich panel the weight of the van would be about 300kg lighter for a 20ft van. If it is better insulated as well and just as strong or stronger why wouldn't you go that way. Cheers Glen
PS In my original post I mistakenly referred to steel framing - of course its aluminium or timber.
0
FollowupID: 752694

Follow Up By: Member - Carl- Saturday, Feb 11, 2012 at 07:47

Saturday, Feb 11, 2012 at 07:47
I would certainly have to disagree with Peter's "most serious off roads van are fiberglass".

Bushtracker gal steel chassis, Al frame and cladding
Kedron Gal steel chassis Al frame and cladding
Spinifex Gal steel chassis Al frame and cladding
Free spirit Al chassis, Al frame and cladding

So that covers the top 4 off road caravans brands

Phonix fiberglass
Trackmaster both al cladding and fiberglass
Supreme getaway gla steel chassis Wood frame Al cladding
Patriot fiberglass

0
FollowupID: 752695

Follow Up By: Member - Wamuranman - Saturday, Feb 11, 2012 at 07:56

Saturday, Feb 11, 2012 at 07:56
Carl,
I think Peter was referring to motorhomes - not caravans.
But you are correct most seem to use the old method of framing.
But why? Hvae I missed something?
Sandwich panel appears to have significant benefits of weight saving and far better insulation.
Gemhunter is one manufacturer that ONLY uses sandwich panel and I think Sunland Blue Heeler (only) is sandwich panel as examples I can find.
Cheers
0
FollowupID: 752696

Follow Up By: Member - Carl- Saturday, Feb 11, 2012 at 08:04

Saturday, Feb 11, 2012 at 08:04
My apology, you are correct he did say motorhomes.

You are correct about Gemhunter as well. I should also point out that Gemhunter make about 3 caravans a year as well.

Kedron tried fiberglass but rejected it. The reason I do not know however.

Earthcruiser (the most high end off road motorhome maker) use fiberglass but I do not think it is sandwich panel. I think it is a shell.
0
FollowupID: 752697

Follow Up By: Member - bungarra (WA) - Saturday, Feb 11, 2012 at 13:15

Saturday, Feb 11, 2012 at 13:15
Ww have recently taken delivery of our new off road caravan from the link below
http://www.explorex.com.au/

This 'van is galv. steel chassis, steel framed and aluminium sheet clad. Yes we did look at the other manufactures listed in the previous posts and made our decision to run with these people.

They also manufacture a lot for the mining/drillng industry and so that speaks for itself...they are seriously worth consideration

No affliation etc...... but a very satisified customer and we have given it some good tests when off road prospecting etc.

sheers
Life is a journey, it is not how we fall down, it is how we get up.
VKS 1341

Member
My Profile  My Position  Send Message

0
FollowupID: 752719

Reply By: Member - Alan H (QLD) - Saturday, Feb 11, 2012 at 08:19

Saturday, Feb 11, 2012 at 08:19
Use of a sandwich panel would make running wires, pipes etc inside of walls a little tricky. But I guess they are ways to run wires - maybe requires a lot of cupboards so that wires can be along walls in the back of the cupboards????

Alan
AnswerID: 477472

Follow Up By: Ray - Saturday, Feb 11, 2012 at 08:52

Saturday, Feb 11, 2012 at 08:52
Would not the same apply to motorhomes?
0
FollowupID: 752702

Reply By: Member - DAZA (QLD) - Saturday, Feb 11, 2012 at 09:35

Saturday, Feb 11, 2012 at 09:35
How do they repair the Sandwich Panels if they are damaged in an accident ect.

Cheers
AnswerID: 477478

Follow Up By: Member - Wamuranman - Saturday, Feb 11, 2012 at 09:44

Saturday, Feb 11, 2012 at 09:44
Thats a good point Daza. I guess they might just replace the whole panel. If a framed caravan is damaged & dented I guess it would be a big repair job as well. But apparently the sandwich panels are quite tough - will not dent etc by grazing van against an object (based on what I've read).
Does anyone know why Kedron rejected this method of manufacture - I would respect their judgement if the reason was compelling?
0
FollowupID: 752710

Reply By: Racey - Saturday, Feb 11, 2012 at 09:47

Saturday, Feb 11, 2012 at 09:47
The debate on framing, metal versus timber, has been going for years and I guess it will continue now we have the sandwich. When choosing an "off road" van the important thing is to go to the recognized manufacturers. As already mentioned they also use different framing materials. More recently Trackmaster have started using the sandwich panels. Personally we have and Evernew which has a timber frame. One thing I always remember in the aircraft industry, all metal frames, wings etc have a fatigue life, whereas the timber frames don't.

Just my six penneths worth.

Cheers

Racey
AnswerID: 477481

Follow Up By: pop2jocem - Saturday, Feb 11, 2012 at 11:34

Saturday, Feb 11, 2012 at 11:34
Racey, "six penneths worth" ok I'll show my age too and add my zacs worth...lol.

As you mentioned about aircraft construction and the advances in technology, 30 or 40 years ago who would have foreseen building aircraft out of what is to some degree plastic and fibreglass (yeah I know not what kids toys are made of) but that is exactly what Boeing are doing. Maybe the same applies to caravan, and for that matter, motorhome construction materials and methods. With emission regulations and fuel usage requirements lighter has several advantages as long as strength is not compromised. I remember when we had a strong earthquake many brick houses suffered damage and some were a total re-construction whereas our timber framed house swayed about and suffered no damage whatsoever.
Just a thought

Cheers
Pop
0
FollowupID: 752717

Reply By: Gone Bush (WA) - Saturday, Feb 11, 2012 at 10:29

Saturday, Feb 11, 2012 at 10:29
I recently had some external panel damage to my Bushtracker repaired at their factory.

There's no doubt in my mind that the damage would have been just as bad if it was fibreglass but it would have been many, many times more expensive.

The entire side panel would have to have been replaced, along with removal, and re-fitting of everything attached to it on the inside.

As it was, just the lengths of alloy panel that were affected were replaced.




I'm glad I ain't too scared to be lazy
- Augustus McCrae (Lonesome Dove)

Lifetime Member
My Profile  My Blog  Send Message

AnswerID: 477484

Reply By: Peter_n_Margaret - Saturday, Feb 11, 2012 at 13:12

Saturday, Feb 11, 2012 at 13:12
The hang up here is conservatism and ''knowing what you know''.

How do you think you would get on if you tried to convince the luxury boat industry to go back to wooden frames with plywood attached? They would laugh at you and so would their customers.

It is undoubtably true that FRP sandwich is more expensive than conventional frame and cladding, especially the material cost, but construction labour would be much cheaper. Most manufacturers (and customers) are driven by cost.

Conventional consruction becomes a ''Catch 22''. They need to be heavy to be strong. That weight means they need to be even stronger (and heavier). That is a really bad downwards spiral if serious off road is remotely on the agenda.

Are fibreglass boats difficult to repair? Not at all, unless you are a cabinet maker.

Fact is thin skin aluminium is not repairable at all. Replacement is the only option short of bog. With fibreglass a repair can be quite localised or very extensive before considering replacement of the panel and the repair will be as strong as the original.

Almost all the wiring inside OKA 196 runs inside cupboards. Having it accessable in this way if necessary is a great bonus. Just needs a different approach.

Cheers,
Peter
OKA196 Motorhome.
AnswerID: 477489

Follow Up By: Member - Beatit (QLD) - Saturday, Feb 11, 2012 at 18:43

Saturday, Feb 11, 2012 at 18:43
G'day Peter,

I have a Fibreglass boat and a tinnie (no I'm not bragging) but I use them in different situations. The tinnie goes wher there is a likelyhood of scrapes and bangs as it is more durable in that respect. Also dragging it over sand or rocks is a lot less painfull. Still can hole the tinnie but less likely.

Using this experience I would have thought that the same applies if applied to off roading?

Kind regards

Theo
0
FollowupID: 752746

Follow Up By: Shaker - Sunday, Feb 12, 2012 at 10:31

Sunday, Feb 12, 2012 at 10:31
If an ocean racing yacht was built to the same quality standards as an offroad caravan, it would be lucky to get out of its marina berth.

I have seen offroad vans stripped down for repair & the softwood frames are just stapled together, no adhesives, no knees & no gussets.

Arguably, the best form of construction would be GRP sandwich made in female moulds, but it would also be very expensive.
0
FollowupID: 752780

Reply By: Member - Wamuranman - Sunday, Feb 12, 2012 at 09:27

Sunday, Feb 12, 2012 at 09:27
Thanks everyone for your replies. There have been a few points made that I had not thought about. A few expressed the view that sandwich panel could be expensive to repair – but even if this is the case this would be covered by insurance for any major damage.
Thanks Member bungarra for your link to Explorex. They seem a very robust built van (albeit a little “industrial looking” aesthetically). However Explorex are made in WA and I want to buy locally in SEQ so I can see my van being built.
We live within 30 min drive to Bushtracker, Kedron, Sunland, Phoenix, and Spinifex factories.
My current thinking (but my research will continue) is that there appears no compelling reasons not to adopt the new construction technology of sandwich panel and benefit from significant weight savings and better insulation. On this basis currently at the top of my list would be a Blue Heeler (Sunland). If I resort to a framed van my current thinking is a Spinifex.
(I have no association with any of these companies – just doing extensive research before I decide).
Thanks for everyone’s contribution – this forum is a powerful research tool.
Cheers

AnswerID: 477538

Follow Up By: Peter_n_Margaret - Sunday, Feb 12, 2012 at 16:04

Sunday, Feb 12, 2012 at 16:04
Wamuranman, while you are in the area, take a few hours to visit Vanglass in Yandina.
They make sandwich panel.
The guys there are also building vans for their own use.
Have a look here...http://caravanersforum.com/viewtopic.php?f=2&t=17786&p=346251&hilit=sandwich+panel#p346251

Cheers,
Peter
OKA196 Motorhome
0
FollowupID: 752816

Follow Up By: Peter_n_Margaret - Sunday, Feb 12, 2012 at 16:27

Sunday, Feb 12, 2012 at 16:27
Correction....
Looks like they will also build (or part build) one of these for you.
Maybe this will also apply to the full van under construction too?
http://vanglass.homestead.com/Crossovercamper.html

Cheers,
Peter
OKA196 Motorhome
0
FollowupID: 752817

Follow Up By: Member - Wamuranman - Sunday, Feb 12, 2012 at 19:24

Sunday, Feb 12, 2012 at 19:24
Thanks peter I will check them out - Yandina is not far away.
Cheers
Glen
0
FollowupID: 752831

Reply By: Pat E - Tuesday, Mar 06, 2012 at 19:33

Tuesday, Mar 06, 2012 at 19:33
I have just been to a caravan repair shop in QLD and was shown a near new van that as in for repair. It was a timber frame van that had started to leek, the insulation was a joke [very thin and didn't cover the cavity from side to side or top to bottom]. Large holes had been drilled through the sides of the frame for wiring so there was very little timber left.
So yes do your homework there is a lot of rubbish out there.

Cheers
Pat NZ
AnswerID: 479659

Sponsored Links

Popular Products (13)